The saying that people "fight like siblings" shows just how charged sibling conflict can be and how well recognized sibling squabbles are. In spite of how widely acknowledged these squabbles can be, sibling conflict can have several impacts on the sibling pair. It has been shown that increased levels of sibling conflict are related to higher levels of anxiety and depression in siblings, along with lower levels of self-worth and lower levels of academic competence. In addition, sibling warmth is not a protective factor for the negative effects of  anxiety ,  depression , lack of  self-worth  and lower levels of academic competence. This means that sibling warmth does not counteract these negative effects. [ 51 ]  Sibling conflict is also linked to an increase in more risky behavior including: smoking cigarettes, skipping days of school, contact with the police, and other behaviors in Caucasian sibling pairs with the exception of firstborns with younger brothers. Except for the elder brother in this pair sibling conflict is positively correlated with risky behavior, thus sibling conflict may be a  risk factor  for behavioral problems. [ 52 ]
A study on what the topic of the fight was (invasion of personal domain or inequality) also shows that the topic of the fight may have a result on the effects of the conflict. This study showed that sibling conflict over personal domain were related to lower levels of self-esteem, and sibling conflict over perceived inequalities seem to be more related to depressive symptoms. However, the study also showed that greater depressive and anxious symptoms were also related to more frequent sibling conflict and more intense sibling conflict. [ 50 ]


Techniques used by parents to manage their children's conflicts include parental non-intervention, child-centered parental intervention strategies, and more rarely the encouragement of physical conflict between siblings. Parental non-intervention included techniques in which the parent ignores the siblings' conflict and lets them work it out between themselves without outside guidance. In some cases, this technique is chosen to avoid situations in which the parent decides which sibling is in the right and may favor one sibling over the other, however, by following this technique the parent may sacrifice the opportunity to instruct their children on how to deal with conflict. Child-centered parental interventions include techniques in which the parent mediates the argument between the two children and helps them come to an agreement. Using this technique, parents may help model how the children can deal with conflicts in the future; however, parents should avoid dictating the outcome to the children, and make sure that they are mediating the argument making suggestions, allowing the children to decide the outcome. This may be especially important when some of the children have autism. [ 53 ]  Techniques in which parents encourage physical aggression between siblings may be chosen by the parents to help children deal with aggression in the future, however, this technique does not appear to be effective as it is linked to greater conflict levels between children. Parental non-intervention is also linked to higher levels of sibling conflict, and lower levels of sibling warmth. It appears that child-centered parental interventions have the best effect on sibling's relationship with a link to greater levels of sibling warmth and lower levels of sibling conflict. [ 54 ]


Studies on social skill and personality differences between  only children  and children with siblings suggest that overall the presence of a sibling does not have any effect on the child as an adult. [ 55 ]


There have always been some differences between siblings, especially different sex siblings. Often, different sex sibling may consider things to be unfair because their brother or sister is allowed to do certain things because of their gender, while they get to do something less fun or just different. McHale and her colleague conducted a  longitudinal study  using middle-childhood aged children and observed the way in which the parents contributed to stereotypical attitudes in their kids. In their study the experimenters analysed two different types of families, one with the same sex siblings, and the other with different sex siblings, as well as the children's birth order. [ 56 ]  The experiment was conducted using phone interviews, in which the experimenters would ask the children about the activities they performed throughout their day outside of school. [ 56 ]  The experimenters found that in the homes where there were mixed gender kids, and the father held traditional values, the kids also held traditional values and therefore also played gender based roles in the home. [ 56 ]  In contrast, in homes where the father did not hold traditional values, the house chores were divided more equally among his kids. [ 56 ]  However, if fathers had two male children, the younger male tended to help more with household chores, but as he reached his teenage years the younger child stopped being as helpful around the house. However, education may be a  confounder  affecting both the father's attitude and the siblings' behavior, and the mother's attitudes did not have a noticeable impact. [ 56 ]


Anthropologist  Edvard Westermarck  found that children who are brought up together as siblings are desensitized to  sexual attraction  to one another later in life. This is known as the  Westermarck Effect . It can be seen in biological and adoptive families, but also in other situations where children are brought up in close contact, such as the  Israeli   kibbutz  system and the Chinese  shim-pua marriage . [ 57 ] [ 58 ]


Siblings  play a unique role in one another's lives that simulates the companionship of  parents  as well as the influence and assistance of  friends . [ 1 ]  Because siblings often grow up in the same household, they have a large amount of exposure to one another, like other members of the  immediate family . However, though a  sibling relationship  can have both hierarchical and reciprocal elements, [ 2 ]  this relationship tends to be more egalitarian and  symmetrical  than with family members of other generations. Furthermore, sibling relationships often reflect the overall condition of cohesiveness within a family. [ 3 ]


Siblings normally spend more time with each other during their childhood than they do with parents or anyone else; they trust and cherish each other, so betrayal by one sibling could cause problems for that person physically as well as mentally and emotionally. Sibling relationships are often the longest-lasting relationship in individuals' lives. [ 2 ] [ 4 ]


The content and context of sibling relationships varies between cultures. [ 5 ]  In  industrialized cultures , sibling relationships are typically discretionary. People are encouraged to stay in contact and cooperate with their brothers and sisters, but this is not an obligation. Older siblings in these cultures are sometimes given responsibilities to watch over a younger sibling, but this is only occasional, with parents taking on the primary role of caretaker. In contrast, close sibling relationships in  nonindustrialized cultures  are often obligatory, with strong cultural norms prompting cooperation and close proximity between siblings. In  India , the brother-sister sibling relationship is so cherished that a festival is held in observance called Raksha Bandhan. At this celebration, the sister presents the brother with a woven bracelet to show their lasting bond even when they have raised their own families. [ 6 ]  These cultures also extend caregiving roles to older siblings, who are constantly expected to watch over younger siblings.


A relationship begins with the introduction of two siblings to one another. Older siblings are often made aware of their soon-to-be younger brother or sister at some point during their mother's pregnancy, which may help facilitate adjustment for the older child and result in a better immediate relationship with the newborn. [ 7 ]  Parents pay attention not only to the newborns but to the older children to avoid sibling rivalry; interactions that can contribute to the older sibling's social aptitude can cognitively stimulate the younger sibling. [ 8 ]  Older siblings even adapt their speech to accommodate for the low language comprehension of the younger sibling, much like parents do with  baby talk . [ 9 ]


The  attachment theory  used to describe an infant's relationship to a primary caregiver may also be applied to siblings. If an infant finds an older sibling to be responsive and sees him or her as a source of comfort, a supportive bond may form. [ 10 ]  On the contrary, a negative bond may form if the older sibling acts in an aggressive, neglectful, or otherwise negative manner. Sibling attachment is further accentuated in the absence of a primary caregiver when the younger sibling must rely on the older one for security and support. [ 11 ]


Even as siblings age and develop, their relationships have considerable stability from infancy through middle childhood, during which positive and negative interactions remain constant in frequency. [ 12 ]  Still, this time period marks great changes for both siblings. Assuming an age gap of only a few years, this marks the time when the older sibling is beginning school, meeting peers, and making friends. This shift in environment reduces both children's access to one another and depletes the older sibling's dependency on the younger for social support, which can now be found outside the relationship. When the younger sibling begins school, the older sibling may help him or her become acclimated and advise on the new struggles that come with being a student. At the same time, the older sibling is also available to answer questions and discuss topics that the younger sibling may not feel comfortable bringing up with a parent. [ 13 ]


The nature of sibling relationships changes from childhood to  adolescence . While young adolescents often provide one another with warmth and support, [ 14 ]  this period of development is also marked by increased conflict [ 15 ]  and emotional distance. [ 16 ]  However, this effect varies based on the sex of siblings. Mixed-sex sibling pairs often experience more drastic decreases in intimacy during adolescence, while same-sex sibling pairs experience a slight rise in intimacy during early adolescence followed by a slight drop. [ 17 ]  In both instances, intimacy once again increases during young adulthood. This trend may be the result of an increased emphasis on peer relationships during adolescence. Often, adolescents from the same family adopt differing lifestyles which further contributes to emotional distance between one another. [ 18 ]


Siblings may influence one another in much the same way that peers do, especially during adolescence. These relationships may even compensate for the negative psychological impact of not having friends [ 19 ]  and may provide individuals with a sense of self-worth. [ 20 ]  Older siblings can effectively model good behaviour for younger siblings. For instance, there is evidence that communication about safe sex with a sibling may be just as effective as with a parent. [ 21 ]  Conversely, an older sibling may encourage risky sexual behaviour by modelling a sexually advanced lifestyle, and younger siblings of teen parents are more likely to become teen parents themselves. [ 19 ]


Research on adolescents suggests positive sibling influences can promote healthy and adaptive functioning [ 22 ] [ 23 ] [ 24 ]  while negative interactions can increase vulnerabilities and problem behaviours. [ 25 ] [ 26 ]  Intimate and positive sibling interactions are an important source of support for adolescents and can promote the development of prosocial behaviour. [ 27 ]  However, when sibling relationships are characterized by conflict and aggression, they can promote delinquency, and antisocial behaviour among peers. [ 28 ]


When siblings reach adulthood, it is more likely that they will no longer live in the same place and that they will become involved in jobs, hobbies, and romantic interests that they do not share and therefore cannot use to relate to one another. In this stage the common struggles of school and being under the strict jurisdiction of parents is dissolved. Despite these factors, siblings often maintain a relationship through adulthood and even old age. [ 29 ]  Proximity is a large factor in maintaining contact between siblings; those who live closer to one another are more likely to visit each other frequently. In addition, gender also plays a significant role. [ 30 ]  Sisters are most likely to maintain contact with one another, followed by mixed-gender dyads. Brothers are least likely to contact one another frequently.


Communication is especially important when siblings do not live near one another. Communication may take place in person, over the phone, by mail, and with increasing frequency, by means of online communication such as email and social networking. Often, siblings will communicate indirectly through a parent or a mutual friend of relative. [ 31 ]  Between adult and elderly siblings, conversations tend to focus on family happenings and reflections of the past. [ 32 ]


In adulthood, siblings still perform a role similar to that of friends. [ 5 ]  Friends and siblings are often similar in age, with any age gap seeming even less significant in adulthood. Furthermore, both relationships are often egalitarian in nature, although unlike sibling relationships, friendships are voluntary. The specific roles of each relationship also differ, especially later in life. For elderly siblings, friends tend to act as companions while siblings play the roles of confidants. [ 33 ]


It is difficult to make long-term assumptions about adult sibling relationships, as they may rapidly change in response to individual or shared life events. [ 34 ] [ 35 ]  Marriage of one sibling may either strengthen or weaken the sibling bond. The same can be said for change of location, birth of a child, and numerous other life events. However, divorce or widowhood of one sibling or death of a close family member most often results in increased closeness and support between siblings.


Sibling relationships are important within the family system. Family systems theory (Kerr and Bowen, 1988) is a theory of human behavior that defines the family unit as a complex social system, in which members interact to influence each other's behavior [ 36 ]  These relationships have an effect on child development, behavior, and support throughout their life span. A child's development is influenced by the dynamic system as a result of the family system. The relationship between siblings is the most important, but isn't focused on as much as other family relationships. Within the family system, not all roles amongst siblings are the same or shared. [ 37 ]  An older sibling can be placed in a position to fulfill the shoes of a parental role. This makes the older sibling a role model and caretaker to the younger sibling. A positive impact on the younger siblings' development may occur. [ 38 ]


Sibling rivalry describes the competitive relationship or animosity between siblings, blood-related or not. Often competition is the result of a desire for greater attention from parents. However, even the most conscientious parents can expect to see sibling rivalry in play to a degree. Children tend to naturally compete with each other for not only attention from parents but for recognition in the world.


Siblings generally spend more time together during childhood than they do with parents. The sibling bond is often complicated and is influenced by factors such as parental treatment,  birth order , personality, and people and experiences outside the family. [ 39 ]  According to  child psychologist   Sylvia Rimm , sibling rivalry is particularly intense when children are very close in age and of the same gender, or where one child is  intellectually gifted . [ 40 ]  Sibling rivalry involves aggression and insults, especially between siblings close in age.


Siblings may be jealous of and harbor resentment toward one another. The main causes of sibling rivalry are lack of social skills, concerns with fairness, individual temperaments, special needs, parenting style, parent's conflict resolution skills and culture. [ 41 ]  In many families, the children count their siblings among their friends. But it's also common for siblings to be great friends on one day and hateful to one another on the next. [ 41 ]


There are many things that can influence and shape sibling rivalry. According to Kyla Boyse from the University of Michigan, each child in a family competes to define who they are as individuals and want to show that they are separate from their siblings. Children may feel they are getting unequal amounts of their parents' attention, discipline, and responsiveness. Children fight more in families where there is no understanding that fighting is not an acceptable way to resolve conflicts, and no alternative ways of handling such conflicts. Stress in the parents' and children's lives can create more conflict and increase sibling rivalry. [ 42 ]


Sigmund Freud  saw the sibling relationship as an extension of the  Oedipus complex , where brothers were in competition for their mother's attention and sisters for their father's. [ 43 ]  For example, in the case of  Little Hans , Freud postulated that the young boy's fear of horses was related to jealousy of his baby sister, as well as the boy's desire to replace his father as his mother's mate. This view has been largely discredited by modern research.


Formulated by  Robert Trivers ,  parent-offspring theory  is important for understanding sibling dynamics and parental decision-making. Because parents are expected to invest whatever is necessary to ensure the survival of their offspring, it is generally thought that parents will allocate the maximum amount of resources available, possibly to their own detriment and that of other potential offspring. [ 44 ]  While parents are investing as much as possible to their offspring, offspring may at the same time attempt to obtain more resources than the parents are able to give to maximize its own reproductive success. Therefore, there is a conflict between the wants of the individual offspring and what the parent is able or willing to give. [ 44 ]  An extension of Trivers' theory leads to predict that it will pay siblings to compete intensely with one another. It can pay to be selfish even to the detriment of not only one's parents but also to one's siblings, as long as the total fitness benefits of doing do outweigh the total costs. [ 45 ]


Alfred Adler  saw siblings as "striving for significance" within the family and felt that  birth order  was an important aspect of personality development. The feeling of being replaced or supplanted is often the cause of jealousy on the part of the older sibling. [ 46 ]  In fact, psychologists and researchers today endorse the influence of birth order, as well as age and gender constellations, on sibling relationships. A child's personality can also have an effect on how much sibling rivalry will occur in a home. Some kids seem to naturally accept changes, while others may be naturally competitive, and exhibit this nature long before a sibling enters the home. [ 46 ]  However, parents are seen as capable of having an important influence on whether they are competitive or not. [ 47 ]


David Levy  introduced the term "sibling rivalry" in 1941, claiming that for an older sibling "the aggressive response to the new baby is so typical that it is safe to say it is a common feature of family life." [ 48 ]  Researchers today generally endorse this view, noting that parents can ameliorate this response by being vigilant to favoritism and by taking appropriate preventative steps. [ 49 ]  In fact, say researchers, the ideal time to lay the groundwork for a lifetime of supportive relationships between siblings is during the months prior to the new baby's arrival. [ 50 ]


According to observational studies by Judy Dunn, children as early as one may be able to exhibit self-awareness and perceive difference in parental treatment between themselves and a sibling and early impressions can shape a lifetime relationship with the younger sibling. [ 39 ]  From 18 months on siblings can understand family rules and know how to comfort and be kind to each other. By 3 years old, children have a sophisticated grasp of social rules, can evaluate themselves in relation to their siblings, and know how to adapt to circumstances within the family. [ 39 ]  Whether they have the drive to adapt, to get along with a sibling whose goals and interests may be different from their own, can make the difference between a cooperative relationship and a rivalrous one. [ 39 ]


Studies have further shown that the greatest sibling rivalry tends to be shown between brothers, and the least between sisters. Naturally, there are exceptions to this rule. What makes brother/brother ties so rivalrous? Deborah Gold has launched a new study that is not yet completed. But she has found a consistent theme running through the interviews she's conducted thus far. "The thing that rides through with brothers that doesn't come across in other sibling pairs is this notion of parental and societal comparison. Somehow with boys, it seems far more natural to compare them, especially more than with sister/brother pairs. Almost from day one, the fundamental developmental markers—who gets a tooth first, who crawls, walks, speaks first—are held up on a larger-than-life scale. And this comparison appears to continue from school to college to the workplace. Who has the biggest house, who makes the most money, drives the best car are constant topics of discussion. In our society, men are supposed to be achievement-oriented, aggressive. They're supposed to succeed." [ 39 ]


Sibling rivalry often continues throughout childhood and can be very frustrating and stressful to parents. [ 42 ]  Adolescents fight for the same reasons younger children fight, but they are better equipped physically and intellectually to hurt and be hurt by each other. Physical and emotional changes cause pressures in the teenage years, as do changing relationships with parents and friends. Fighting with siblings as a way to get parental attention may increase in adolescence. [ 51 ]  One study found that the age group 10 to 15 reported the highest level of competition between siblings. [ 52 ]


However, the degree of sibling rivalry and conflict is not constant. Longitudinal studies looking at the degree of sibling rivalry throughout childhood from Western societies suggest that, over time, sibling relationships become more egalitarian and this suggest less conflict. [ 53 ]  Yet, this effect is moderated by birth order: Older siblings report more or less the same level of conflict and rivalry throughout their childhood. In contrast, young siblings report a peak in conflict and rivalry around young adolescence and a drop in late adolescence. The decline in late adolescence makes sense from an evolutionary perspective: Once resources cease and/ or individuals have started their own reproductive career, it makes little sense for sibling to continue fierce competition over resources that do not affect their reproductive success anymore. [ 54 ]


Sibling rivalry can continue into adulthood and sibling relationships can change dramatically over the years. Events such as a parent's illness may bring siblings closer together, whereas marriage may drive them apart, particularly if the in-law relationship is strained. Approximately one-third of adults describe their relationship with siblings as rivalrous or distant. However, rivalry often lessens over time. At least 80 percent of siblings over age 60 enjoy close ties. [ 39 ]


Parents can reduce the opportunity for rivalry by refusing to compare or typecast their children, [ 55 ]  teaching the children positive ways to get attention from each other and from the parent, planning fun family activities together, and making sure each child has enough time and space of their own. [ 42 ]  They can also give each child individual attention, encourage teamwork, refuse to hold up one child as a role model for the others, and avoid favoritism. [ 56 ]  It is also important for parents to invest in time spent together as a whole family. Children who have a strong sense of being part of a family are likely to see siblings as an extension of themselves. However, according to Sylvia Rimm, although sibling rivalry can be reduced it is unlikely to be eliminated. In moderate doses, rivalry may be a healthy indication that each child is assertive enough to express his or her differences with other siblings. [ 40 ]


Weihe [ 57 ]  suggests that four criteria should be used to determine if questionable behavior is rivalry or  sibling abuse . First, one must determine if the questionable behavior is age appropriate: e.g., children use different conflict-resolution tactics during various developmental stages. Second, one must determine if the behavior is an isolated incident or part of an enduring pattern: abuse is, by definition, a long-term pattern rather than occasional disagreements. Third, one must determine if there is an "aspect of victimization" to the behavior: rivalry tends to be incident-specific, reciprocal and obvious to others, while abuse is characterized by secrecy and an imbalance of power. Fourth, one must determine the goal of the questionable behavior: the goal of abuse tends to be embarrassment or domination of the victim.
Parents should remember that sibling rivalry today may someday result in siblings being cut off from each other when the parents are gone. Continuing to encourage family togetherness, treating siblings equitably, and using family counseling to help arrest sibling rivalry that is excessive may ultimately serve children in their adult years.


While  cousin marriage  is legal in most countries, and  avunculate marriage  is legal in many, sexual relations between siblings are considered  incestuous  almost universally [ citation needed ] . Innate sexual aversion between siblings forms due to close association in childhood, in what is known as the  Westermarck effect . Children who grow up together do not normally develop sexual attraction, even if they are unrelated, and conversely, siblings who were separated at a young age may develop sexual attraction.


Thus, many cases of sibling incest, including  accidental incest , concern siblings who were separated at birth or at a very young age. [ 59 ]  One study from New England has shown that roughly 10% of males and 15% of females had experienced some form of sexual contact with a  brother  or  sister , with the most common form being fondling or touching of one another's  genitalia . [ 60 ]


John M. Goggin and William C. Sturtevant (1964) listed eight societies which generally allowed sibling marriage, and thirty-four societies where sibling marriage was permissible among certain classes only. [ 61 ]


A historical marriage that took place between full siblings was that between  John V, Count of Armagnac  and Isabelle d'Armagnac, dame des Quatre-Vallées, c. 1450. The provided  papal dispensation  for this union was declared forged in 1457. [ 62 ]  The marriage was declared invalid and the children were declared bastards and removed from the line of succession.


In antiquity,  Laodice IV , a  Seleucid  princess, priestess, and queen, married all three of her brothers in turn.
Sibling marriage was especially frequent in  Roman Egypt , and probably even the preferred norm among the nobility. [ 63 ] [ 64 ]  In most cases, marriage of siblings in Roman Egypt was a result of the religious belief in divinity and maintaining purity. Based on the model from the myth of  Osiris  and  Isis , it was considered necessary for a god to marry a goddess and vice versa. This led to Osiris marrying his sister Isis due to limited options of gods and goddesses to marry. In order to preserve the divinity of ruling families, siblings of the royal families would marry each other. [ 65 ]


Sibling marriage is also common among the  Zande people  of Central Africa. [ citation needed ]


In a number of European countries such as Belgium, France, Luxembourg, the Netherlands and Spain, marriage between siblings remains prohibited, but incest between siblings is no longer prosecuted. [ 66 ]


According to  Cavanagh Johnson & Friend (1995) , between forty and seventy-five percent of children will engage in some sort of sexual behavior before reaching 13 years of age. [ 67 ]  In these situations, children are exploring each other's bodies while also exploring gender roles and behaviors, and their sexual experimentation does not indicate that these children are child sex offenders. As siblings are generally close in age and locational proximity, the opportunity for sexual exploration between siblings is fairly high and that, if simply based on mutual curiosity, then these activities are not harmful or distressing, either in childhood or later in adulthood. [ 68 ] [ full citation needed ]  According to  Reinisch (1990) , studying early sexual behavior generally, over half of all six- and seven-year-old boys have engaged in sex play with other boys, and more than a third of them with girls, while more than a third of six- and seven-year-old girls have engaged in such play with both other girls and with boys. [ 69 ]  This play includes  playing doctor , mutual touching, and attempts at simulated, non-penetrative intercourse. [ 69 ]  Reinisch views such play as part of a normal progression from the sensual elements of bonding with parents, to masturbation, and then to sex play with others. [ 69 ]  By the age of eight or nine, according to Reinisch, children become aware that sexual arousal is a specific type of erotic sensation, and will seek these pleasurable experiences through various sights, self-touches, and fantasy, so that earlier generalized sex play shifts into more deliberate and intentional arousal. [ 69 ]


Abusive incestuous relationships between siblings can have adverse effects on the parties involved. Such abuse can leave victims detrimentally hindered in developmental processes, such as those necessary for interpersonal relations, and can be the cause for depression, anxiety, and substance abuse in the victim's adult life. [ 70 ]  Definitions used have varied widely. Child sexual abuse between siblings is defined by the (US) National Task Force on Juvenile Sexual Offending as: sexual acts initiated by one sibling toward another without the other's consent, by use of force or coercion, or where there is a power differential between the siblings. In  Caffaro & Conn-Caffaro (1998) , sibling child sexual abuse is defined as "sexual behavior between siblings that is not age appropriate, not transitory, and not motivated by developmentally, mutually appropriate curiosity". [ 71 ]  When child sexual experimentation is carried out with siblings, some researchers, e.g.  Bank & Kahn (1982) , [ 72 ]  do consider it incest, but those researchers who do use that term distinguish between abusive incest and non-abusive incest. Bank and Kahn say that abusive incest is power-oriented, sadistic, exploitative, and coercive, often including deliberate physical or mental abuse. [ 72 ]


Views of young sibling sexual contact may be affected by more general views regarding sexuality and minors:


Finkelhor & Hotaling (1984) [ 73 ]  consider sexual contact to be abusive only under these circumstances: [ 74 ]


Laviola (1992)  says that behavior that is sexually abusive of children (generally speaking) depends upon the use of power, authority, bribery, or appeal to the child's trust or affection. [ 75 ]


De Jong (1989)  offers four criteria to judge whether sexual behavior involving persons under 14 years old is abusive or not:


According to De Jong, if one or more of these is present, the behavior is abusive, whereas if none is present, the behavior must be considered normal sexual experimentation. [ 76 ]


A  sibling-in-law  is the  spouse  of one's  sibling , the sibling of one's spouse or the person who is married to the sibling of one's spouse. [ 1 ]


More commonly, a sibling-in-law is referred to as a  brother-in-law  for a male sibling-in-law and a  sister-in-law  for a female sibling-in-law.


Sibling-in-law also refers to the reciprocal relationship between a person's spouse and their sibling's spouse. In  Indian English  this can be referred to as a co-sibling (specifically a co-sister, for the wife of one's sibling-in-law, [ 2 ]  or co-brother, for the husband of one's sibling-in-law [ 3 ] ).


Siblings-in-law are related by a type of  kinship  called  affinity  like all in-law relationships. All of these are relations which do not relate to the person directly by blood. [ 1 ]


Just like the children of one's siblings, the children of one's siblings-in-law are called simply  nieces  and  nephews  – if necessary, specified whether "by marriage", as opposed to " by blood " or "by adoption".


If one pair of siblings is married to another pair of siblings, the siblings-in-law are thus doubly related, each of the four both through one's spouse and through one's sibling, while the children of the two couples are  double cousins .


One study, examining the issue of envy in the triadic system of sibling, sibling-in-law and spouse, concluded that "The sibling-in-law relationship shared similarities with both  spousal  and  sibling relationships " and that "Relational closeness and satisfaction for all relationships in the triad were correlated." [ 4 ]


In  Islamic law  (Sharia) [ 5 ]  and  Jewish law  ( halakha ), [ 6 ]  sexual relations between siblings-in-law are prohibited as incestuous, unless the spouse is no longer married. Conversely, in Judaism there was the custom of  yibbum , whereby a man had a non-obligatory duty to wed his deceased brother's childless widow, so she might have progeny by him. [ 7 ]


Sippenhaft  or  Sippenhaftung  ( German:   [ˈzɪpənˌhaft(ʊŋ)] ,  kin liability ) is a German term for the idea that a family or clan shares the responsibility for a crime or act committed by one of its members, justifying  collective punishment . [ 1 ] [ 2 ]  As a legal principle, it was derived from  Germanic law  in the  Middle Ages , usually in the form of fines and compensations. It was adopted by  Nazi Germany  to justify the punishment of kin (relatives, spouse) for the offence of a family member. Punishment often involved imprisonment and execution, and was applied to relatives of the conspirators of  the failed  1944 bomb plot to assassinate Hitler .


Prior to the adoption of  Roman law  and  Christianity ,  Sippenhaft  was a common legal principle among Germanic peoples, including  Anglo-Saxons  and  Scandinavians . [ 3 ]  Germanic laws distinguished between two forms of justice for severe crimes such as murder:  blood revenge , or  extrajudicial killing ; and  blood money , pecuniary restitution or fines in lieu of revenge, based on the  weregild  or "man price" determined by the victim's wealth and social status. [ 4 ]  The principle of  Sippenhaft  meant that the family or clan of an offender, as well as the offender, could be subject to revenge or could be liable to pay restitution. [ 5 ]  Similar principles were common to  Celts ,  Teutons , and  Slavs . [ 6 ]


In Nazi Germany, the term was revived to justify the punishment of kin (relatives, spouse) for the offence of a family member. In that form of  Sippenhaft , the relatives of persons accused of crimes against the state were held to share the responsibility for those crimes and subject to arrest and sometimes execution.


Examples of  Sippenhaft  being used as a threat exist within the  Wehrmacht  from around 1943. Soldiers accused of having "blood impurities" or soldiers conscripted from outside of Germany also began to have their families threatened and punished with  Sippenhaft . An example is the case of  Panzergrenadier  Wenzeslaus Leiss, who was accused of desertion on the  Eastern Front  in December 1942. After the  Düsseldorf   Gestapo  discovered supposed Polish links in the Leiss family, in February 1943 his wife, two-year-old daughter, two brothers, sister and brother-in-law were arrested and executed at  Sachsenhausen concentration camp . By 1944, several general and individual directives were ordered within divisions and corps, threatening troops with consequences against their families.


Many people who had committed no crimes were arrested and punished under  Sippenhaft  decrees introduced after the failed  20 July plot  to assassinate  Adolf Hitler  in July 1944. [ 7 ] : 121–166  After the failure of the 20 July plot, the  SS  chief  Heinrich Himmler  told a meeting of  Gauleiters  in  Posen  that he would "introduce absolute responsibility of kin ... a very old custom practiced among our forefathers". According to Himmler, this practice had existed among the ancient  Teutons . "When they placed a family under the ban and declared it outlawed or when there was a  blood feud  in the family, they were utterly consistent. ... This man has committed treason; his blood is bad; there is traitor's blood in him; that must be wiped out. And in the blood feud the entire clan was wiped out down to the last member. And so, too, will  Count Stauffenberg 's family be wiped out down to the last member." [ 8 ]  Accordingly, the members of the family of von Stauffenberg (the officer who had planted the bomb that failed to kill Hitler) were all under suspicion. His wife,  Nina Schenk Gräfin von Stauffenberg , was sent to  Ravensbrück concentration camp  (she survived and lived until 2006). His brother  Alexander , who knew nothing of the plot and was serving with the  Wehrmacht  in Greece , was also sent to a concentration camp. Similar punishments were meted out to the relatives of  Carl Goerdeler ,  Henning von Tresckow ,  Adam von Trott zu Solz  and many other conspirators.  Erwin Rommel  opted to commit suicide, rather than being tried for his suspected role in the plot, in part because he knew that his wife and children would suffer well before his own all-but-certain conviction and execution.


After the 20 July plot, numerous families connected to the Soviet-sponsored  League of German Officers  made up of German prisoners of war, such as those of  Walther von Seydlitz-Kurzbach  and  Friedrich Paulus , were also arrested. Unlike a number of the 20 July conspirators families, those arrested for connection to the League were not released after a few months but remained in prison until the end of the war. Younger children of arrested plotters were not jailed but sent to orphanages under new names. Stauffenberg's children were renamed "Meister". [ 9 ]


After 20 July 1944 these threats were extended to include all German troops, in particular, German commanders. A decree of February 1945 threatened death to the relatives of military commanders who showed what Hitler regarded as cowardice or defeatism in the face of the enemy. After  the surrender of Königsberg  to the Soviets in April 1945, the family of the German commander General  Otto Lasch  were arrested. These arrests were publicized in the  Völkischer Beobachter . [ 7 ] : 53–88


The principle of  Sippenhaftung  is considered incompatible with  German Basic Law , and therefore has no legal definition. [ citation needed ]


A  sister   is a  woman  or a  girl  who shares parents or a parent with another individual; a female  sibling . [ 1 ]  The male counterpart is a  brother . Although the term typically refers to a  familial  relationship, it is sometimes used endearingly to refer to non-familial relationships. [ 2 ]  A full sister is a  first-degree relative .


The  English  word  sister  comes from  Old Norse   systir  which itself derives from  Proto-Germanic   *swestēr ,  both of which have the same meaning, i.e. sister. Some studies have found that sisters display more traits indicating jealousy around their siblings than their male counterparts,  brothers . [ 3 ]  In some cultures, sisters are afforded a role of being under the protection by male siblings, especially older brothers, from issues ranging from bullies or sexual advances by womanizers. [ 4 ]  In some quarters, the term  sister  has gradually broadened its colloquial meaning to include individuals stipulating  kinship . [ 5 ]  In response, in order to avoid equivocation, some publishers prefer the usage of  female sibling  over  sister . [ 6 ]  Males with a  twin  sister sometimes view her as their female  alter ego , or what they would have been like if they had two X chromosomes. [ 7 ]  A study in Perth, Australia found that girls having only youngers brothers resulted in a  chastity effect : losing their  virginity  on average more than a year later than average. This has been hypothesized as being attributed to the pheromones in their brothers' sweat and household-related errands. [ 8 ]


Various studies have shown that older sisters are likely to give a varied  gender role  to their younger siblings, as well as being more likely to develop a close bond with their younger siblings. [ 9 ]  Older sisters are more likely to play with their younger siblings. [ 10 ]  Younger siblings display more needy behavior when near their older sister [ 11 ]  and are more likely to be tolerant of an older sister's bad behavior. [ 12 ]  Boys with only one older sister are more likely to display stereotypically male behavior, and such  masculine  boys increased their masculine behavior with the more sisters they have. [ 13 ]  The reverse is true for young boys with several sisters, as they tend to be  feminine , however, they outgrow this by the time they approach  pubescence . [ 14 ]  Boys with older sisters were less likely to be delinquent or have  emotional and behavioral disorders . [ 15 ]  A younger sister is less likely to be scolded by older siblings than a younger brother. [ 16 ]  The most common recreational activity between older brother/younger sister pairs is art drawing. [ 9 ]  Some studies also found a correlation between having an older sister and constructive discussions about safe sexual practices. [ 17 ]  Some studies have shown that men without sisters are more likely to be ineffectual at courtship and romantic relationships. [ 18 ]


Social Bonding and Nurture Kinship: Compatibility between Cultural and Biological Approaches  is a book on human  kinship  and social behavior by Maximilian Holland, published in 2012. The work synthesizes the perspectives of  evolutionary biology ,  psychology  and  sociocultural anthropology  towards understanding human social bonding and cooperative behavior. It presents a theoretical treatment that many consider to have resolved longstanding questions about the proper place of genetic (or 'blood') connections in human kinship and social relations, and a synthesis that "should inspire more nuanced ventures in applying Darwinian approaches to sociocultural anthropology". [ 1 ]


The aim of the book is to show that "properly interpreted, cultural anthropology approaches (and ethnographic data) and biological approaches are perfectly compatible regarding processes of social bonding in humans." [ 2 ]  Holland's position is based on demonstrating that the dominant biological theory of social behavior ( inclusive fitness  theory) is typically misunderstood to predict that genetic ties are necessary for the  expression  of social behaviors, whereas in fact the theory only implicates genetic associations as necessary for the  evolution  of social behaviors. Whilst rigorous evolutionary biologists have long understood the distinction between these levels of analysis (see  Tinbergen's four questions ), past attempts to apply inclusive fitness theory to humans have often overlooked the distinction between  evolution  and  expression . [ 3 ]


Beyond its central argument, the broader philosophical implications of Holland's work are considered by commentators to be that it both "helps to untangle a long-standing disciplinary muddle" [ 4 ]  and "clarifies the relationship between biological and sociocultural approaches to human kinship." [ 5 ]   It is claimed that the book "demonstrates that an alternative non-deterministic interpretation of evolutionary biology is more compatible with actual human social behavior and with the frameworks that sociocultural anthropology employs" [ 6 ]  and as a consequence, delivers "a convincing, solid and informed blow to the residual genetic determinism that still influences the interpretation of social behaviour." [ 7 ]


The book's form consists of a cumulative argument (using a wide range of supporting evidence) made over nine chapters, with each chapter ending in a brief retrospective summary, and the final chapter containing a recapitulation and summary of the whole, [ 8 ]  and drawing some wider conclusions.


Holland begins by tracing transitions in the history of anthropological theories of social behavior and  kinship , noting the varying importance with which 'blood ties' have been understood to be a necessary element of human kinship and social relations. He suggests that whilst the mounting  ethnographic  evidence has led to a move away from the 'blood kinship' concept in recent decades, many sociocultural anthropologists still query the connection between kinship and blood, reproduction or some other apparently biological functions. Meanwhile, many biologists,  biological anthropologists  and  evolutionary psychologists  have persisted in viewing human kinship and cooperative behavior as necessarily associated with genetic relationships and 'blood ties'. The current situation has been characterized as "a clash between incommensurate paradigms, holding as they may, completely incompatible ideas about human nature." [ 9 ]  Holland argues that a clear resolution to these questions is still outstanding, and would therefore be of value. In closing the introduction, Holland writes; "The approach is not reductive. The claim is rather that a thorough investigation of the 'biological facts' can be useful mainly though allowing a change in focus... away from confusion about the place of genealogy in social ties, and onto a reformulated baseline, built around varied  processual aspects of social bonding. " [ 10 ]


The book reviews the background and key elements of  Hamilton's   inclusive fitness  theory from the 1960s onwards, setting out its significant conceptual and heuristic value. Holland notes that Hamilton acknowledged that his earliest and most widely known account (1964) [ 11 ]  contained technical inaccuracies. He also notes Hamilton's early speculations about possible proximate mechanisms of the expression of social behavior ( supergenes [ 11 ]  as a possible alternative to  behaviour-evoking-situations [ 11 ] ) contained errors that have nevertheless remained very influential in popular accounts. Specifically, the supergenes notion (sometimes called the  Green-beard effect ) - that organisms may evolve genes that are able to identify identical copies in others and preferentially direct social behaviours towards them - was theoretically clarified and withdrawn by Hamilton in 1987. [ 12 ]  However, in the intervening years, the notion that supergenes (or more often, simply individual organisms) have evolved  to identify genetic relatives and preferentially cooperate with them  took hold, and became the way many biologists came to understand the theory. This persisted, despite Hamilton's 1987 correction. In Holland's view it is the pervasiveness of this longstanding but erroneous perspective, and the suppression of the alternative 'behaviour-evoking-situations' perspective regarding social expression mechanisms, that is largely responsible for the ongoing clash between biological and sociocultural approaches to human kinship.


Holland shows that, in the 1970s and 80s, the first wave of attempts (known as  human  sociobiology  or  Darwinian anthropology ) to apply inclusive fitness theory to human social behavior relied on, and further reinforced, this same misinterpretation (above section) about the theory's predictions and the proximate mechanisms of social behavior. Holland also shows that this period of research was burdened with many misplaced assumptions about  universal  attributes of the human sexes,  sexuality  and  gender  roles, apparently projected from the  specific cultural values  of the researchers themselves. Holland also shows that, following the perceived failures of this early wave, and particularly its methodological agnosticism regarding proximate mechanisms of social behavior, the  evolutionary psychology  school grew up in its place. Although this latter school typically avoided engaging with the ethnographic data on human kinship, Holland argues that in the few cases where it did so, it repeated the misinterpretation of inclusive fitness theory that characterized the first wave. Holland also notes that  Kitcher , in his [ 13 ]  1985 critique of the sociobiological position, suggested that perhaps the expression of social behaviors in humans might quite simply be based on cues of context and familiarity, rather than genetic relatedness  per se .


Chapters four and five investigate further the theory and evidence surrounding the  proximate mechanisms  of social behavior; specifically the question of whether social behaviors are expressed by organisms via  behaviour-evoking-situations  or via direct detection of actual genetic relatedness. Related questions have been the domain of  kin recognition  theory. Holland notes that the name 'kin recognition' itself suggests some expectation that a positive identification of genetic relatedness is a prediction of inclusive fitness theory, and is thus expected. Similar points have been made by others; "many behavioural ecologists seem to implicitly assume that specialised mechanisms allowing individuals to distinguish their kin from non-kin must have evolved. [ 14 ] [ 15 ] " Again, the possibility that  behaviour-evoking-situations  might be the more parsimonious [ 16 ]  mechanism of the expression of social behavior, and fully compatible with inclusive fitness theory, has often been underemphasized. However, Holland's review of the evidence notes that field studies in this area quickly established that  behaviour-evoking-situations  do in fact overwhelmingly mediate social behaviours in those species studied, and that, particularly in mammal species, social bonding and familiarity formed in early developmental contexts (e.g. in burrows or nesting sites) are a common mediating mechanism for social behaviors, independently of genetic relatedness  per se . On the basis of the preceding theoretical analysis and review of evidence, at the end of chapter five, Holland argues that;


It is entirely erroneous, both in reference to theory and in reference to the evidence, to claim or suggest that 'the facts of biology' support the claim that organisms have evolved to cooperate with genetic relatives  per se . [ 17 ]


Having argued for the above position on the lack of necessity for genetic relatedness  per se  to mediate social bonding and behavior, Holland suggests that "The further question then is; can we uncover in any greater detail how familiarity and other context-dependent cues operate?". [ 17 ]  To discover the extent to which the variety of human kinship behaviors may nevertheless be compatible with this (less deterministic) interpretation of biological theory of social behavior, Holland suggests that a survey of  primates'  most fundamental social patterns may give clues, especially those of species most closely connected with humans. The variety of primate  mating systems , group-membership (' philopatry ') patterns, and life-cycle patterns are reviewed. Holland finds that;


Like other mammals, Catarrhini primate demographics are strongly influenced by ecological conditions, particularly density and distribution of food sources... Cohesive social groups and delayed natal dispersal mean that maternally related individuals, including maternal siblings, face a statistically reliable context of interaction in all Catarrhini primates. This reliable context of interaction with maternally related individuals is extended amongst those species with female philopatry (especially Cercopithecinae). [ 18 ]


As with other social mammals, evidence suggest that the reliability of 'behaviour-evoking-situations' this social context provides has shaped the mechanisms of proximate expression of social bonding and behavior;


Adoption of infants by females (and sometimes males) demonstrates that care-giving and bonding to infants is not mediated by positive powers of discrimination. From the infant's perspective, it will bond with any responsive carer. If not necessarily the actual mother, in natural conditions this will often be a maternal relative (particularly an older sibling), but the context is primary, not the actual relatedness. Similarly, social bonding and social behaviours between maternal siblings (and occasionally between other maternal relatives) is context-driven in primates, and mediated via the care-giver. [ 19 ]


Holland also notes how  Bowlby  and colleagues'  attachment theory  was strongly informed by primate bonding patterns and mechanisms, and that in Bowlby's later writing the then emerging  inclusive fitness  theory was explicitly linked to.


[Bowlby's] work demonstrated that social attachments form on the basis of provision of care, and responsiveness to elicitations for care. The social context of living together and the familiarity this brings, provides the circumstance within which social bonds can form... [ 19 ]


On the basis of combining more recent primate research with the findings of attachment theory, Holland proposes that "In attempting to define more specific forms of  the giving of care and nurture  which may mediate social bonding we [find] that provision of food is likely to play a part, as well as the more intangible provision of warmth and comfort, and a safe base for sleeping. [ 19 ] "


Holland claims that, while biological theory of social behavior is not  deterministic  in respect of genetic relatedness vis-a-vis the formation of social bonds and expression of social behaviors, evidence does point to compatibility between a  non-reductive  interpretation of the theory and how such bonds and behaviors operate in social mammals, primates and in humans. In the final part of the book, Holland explores the extent to which this perspective is also compatible with sociocultural anthropology's ethnographic accounts of human kinship and social behavior, both occasional accounts from the past, as well as more contemporary accounts that have explicitly eschewed the earlier 'blood ties' assumption. Holland finds that;


Many contemporary accounts focus on social bonds formed in childhood and the importance of the performance of acts of care, including food provision, in mediating these bonds. In all cases it is this performance of care which is considered the overriding factor in
mediating social bonds, notwithstanding 'blood ties'. In short, there is strong compatibility between the perspectives on social bonding that emerge from a proper account of biological theory and those documented by ethnographers. [ 20 ]


Holland's concluding chapter gives a summary of his fundamental position;


A crucial implication of this argument taken as a whole is that  the expression of the kinds of social behaviours treated by inclusive fitness theory does not require genetic relatedness.  Sociobiology and evolutionary psychology's claims that biological science predicts that organisms  will  direct social behaviour towards relatives are thus both  theoretically  and  empirically  erroneous. Such claims and their supporting arguments also give a highly misleading and reductive account of basic biological theory. Properly interpreted,  cultural anthropology approaches (and ethnographic data) and biological approaches are perfectly compatible  regarding processes of social bonding in humans. Most of all, this requires a focus on the circumstances and processes which lead to social bonding. [ 2 ]


The book notes that, as an outcome of the analysis,  Schneider's  sociocultural perspective on human kinship is vindicated;


Do the biological facts have some priority or are they but one of the conditions, like ecology, economy, demography, etc., to which kinship systems must adapt? Take note: if the latter is the case, then kinship must be as much rooted in these other conditions as in the biological facts. [ 21 ]


The author supplies several examples of the insight that Schneider's broad approach can provide. The book closes with an example of a clash of cultural perspectives on kinship and family norms, and makes the suggestion that;


Constructing from narrow cultural particulars (Euro-American or otherwise) an essentialised model of 'human nature' does not constitute science; it is closer to cultural colonialism. In any analysis intended to shed light on proposed universals of the human condition, reflexivity is essential, and cultural and biological approaches both surely necessary. [ 22 ]


Kinship theorist and member of the  US National Academy of Sciences ,  Robin Fox  wrote of the work:


An excellent and constructive discussion of matters in kinship and its cultural and biological components, handsomely reconciling what have been held to be incompatible positions. [ 23 ] Max Holland gets to the heart of the matter concerning the contentious relationship between kinship categories, genetic relatedness and the prediction of behavior. If he had been in the debate in the 1980s then a lot of subsequent confusion could have been avoided" [ 4 ]


Irwin Bernstein, distinguished research professor in the university of Georgia's  Behavioral and Brain Sciences Program  made the following comment on Holland's book:


Max Holland has demonstrated extraordinarily thorough scholarship in his exhaustive review of the often contentious discussions of kinship.  He has produced a balanced synthesis melding the two approaches exemplified in the biological and sociocultural behavioral positions. His work in reconciling opposing views clearly demonstrates the value of interdisciplinary approaches.  This should be the definitive word on the subject. [ 24 ]


Philip Kitcher , John Dewey Professor of Philosophy, and James R. Barker Professorship of Contemporary Civilization at  Columbia University , past president of the  American Philosophical Association  and inaugural winner of the Prometheus Prize, stated of the book:


Max Holland has provided a wide-ranging and deeply-probing analysis of the influence of genetic relatedness and social context on human kinship. He argues that while genetic relatedness may play a role in the evolution of social behavior, it does not determine the forms of such behavior. His discussion is exemplary for its thoroughness, and should inspire more nuanced ventures in applying Darwinian approaches to sociocultural anthropology. [ 1 ]


Kirk Endicott, professor emeritus of  anthropology  at the university of Dartmouth, wrote that Holland's book was:


A brilliant discussion of the relationship between kinship and social bonding as understood in evolutionary biology and in sociocultural anthropology. Among other contributions, it debunks the common misconception that biological evolution involves individual organisms actively pursuing the goal of increasing the numbers of their genes in successive generations, the measure of their so-called 'individual inclusive fitness'. Holland demonstrates that an alternative non-deterministic interpretation of evolutionary biology is more compatible with actual human social behavior and with the frameworks that sociocultural anthropology employs. [ 25 ]


Janet Carsten, kinship theorist and professor of anthropology at the university of Edinburgh stated that:


This book is a scholarly attempt to get beyond the often sterile oppositions between evolutionary and culturalist approaches to kinship. In bringing together two sides of the debate, it constitutes a valuable contribution to kinship studies. [ 26 ]


In a review for the journal  Critique of Anthropology , Nicholas Malone concluded that:


Lucid and effective... Holland has produced a significant work of scholarship that will be of interest to a wide swath of the anthropological community. [ 27 ]


Commenting on the book for the journal  Social Analysis , Anni Kajanus found that:


Holland has done an excellent and thorough job in reviewing the disciplinary and interdisciplinary histories of approaches to kinship and social bonds in anthropology, biology, and psychology. Most importantly, he clarifies the different levels of analysis when looking at human behavior in real time and in the evolutionary time frame. This makes the book essential reading for anyone who acknowledges that human relatedness and social bonds are shaped by the
evolved dispositions of our species, their development through the life-course of an individual, and our specific cultural-historical environments... Holland's book goes a long way toward clarifying and therefore advancing these theoretical debates [ 28 ]


An in-depth review of the book by  primatologist  Augusto Vitale, in the journal  Folia Primatologica , found that:


This is, without a doubt, a very significant and important contribution to the on-going discussion about the determinants of sociality in humans as well as in other animals... A painstaking analysis of inclusive fitness, attachment theory and non-human primate social relationships, through a fascinating journey which ends with an anthropological account of social bonds in different cultures... It is a landmark in the field of evolutionary biology, which places genetic determinism in the correct perspective. [ 7 ]


Stuart Semple, evolutionary anthropologist, reviewing the book in the journal  Acta Ethologica  stated that:


As someone who teaches behavioural ecology to biologists, and primate biology to social and biological anthropologists, I will be strongly recommending this book to all of my advanced undergraduates, masters and PhD students, as well as to my colleagues. Not only does it help to resolve debates that have run for many years, but it is also an outstanding example of what can be achieved by immersing oneself in literature from different fields, while retaining an intellectual openness and exercising incisive analysis. Many of us talk enthusiastically about inter- and multi-disciplinarity, but often this is not much more than lip service. This book is a shining example of what can be achieved when excellent scholars engage fully across disciplinary boundaries. There should be more texts like this. [ 29 ]


In addition to praise for the book's significance, the  Folia Primatologica  review noted that the book is at times too dense and requires close reading;


The argument here and there becomes too detailed and tortuous, but it is absolutely captivating... [Colleagues] who are less used to extremely detailed theoretical reasoning, will find it difficult at the beginning... [ 7 ]


Son preference  is the ancient and cross-cultural human preference for male (rather than female) offspring. Son preference has been demonstrated across all social classes, from "succession laws in royal families to land inheritance in peasant families." [ 1 ]  Sons are considered both a  status symbol  and a genetic and economic  competitive advantage . [ 2 ]


Son preference can influence  birth rates  and thus  population growth . [ 3 ]  Parents will continue having children until they have produced the desired number of sons; there is no equivalent behavior in respect to daughters. [ 4 ]  Families with sons have been shown to have increased levels of "marital stability and marital satisfaction," and the presence of sons may increase  paternal  involvement in child-rearing. [ 4 ]  In the 21st century, son preference has been broadly documented in South and East Asia, [ 3 ]  but is also observable in Western countries. [ 5 ]


An example of son preference is demonstrated by the traditions of the  Igbo people  of Nigeria: "The status of a man is assessed in part by his number of sons. A man with many sons is viewed as a wealthy or an accomplished man." [ 6 ]  Igbo men that die without fathering sons are seen as having been "unaccomplished or a misfit" and are not given ceremonial second burials. [ 7 ]


Son preference is culturally mediated and expression of it may change with circumstances. For example, demonstrations of son preference declined in "subsequent generations" of  Turkish immigrants to Germany . [ 8 ]  Additionally, researchers have found that increasing levels of "gender indifference" and decreasing levels of son preference, for example as documented in Taiwan since 1990, can be correlated to maternal educational levels. [ 9 ]  Son preference in Asian-immigrant households in the United States is higher amongst couples from the same country and higher in mixed-origin marriages where the male partner is the immigrant. [ 10 ]


Son preference may result in  sex selection  practices. Birth of daughters can result in  gender disappointment  in societies that have strong son preference.  Daughter preference  or son preference is sometimes expressed by higher levels of household investment in offspring of preferred gender. [ 1 ]


Gitel (Gertrude) Poznanski Steed  (May 3, 1914 – September 6, 1977) was an American cultural  anthropologist  known for her research in India 1950–52 (and returning in 1970) involving  ethnological  work in three villages to study the complex detail of their social structure. She supplemented her research with thousands of ethnological photographs of the individuals and groups studied, the quality of which was recognised by  Edward Steichen . She experienced chronic illnesses after her return from the field, but nevertheless completed publications and many lectures but did not survive to finish a book  The Human Career in Village India  which was to integrate and unify her many-sided studies of human character formation in the cultural/historical context of India. [ 1 ] [ 2 ]


Gertrude Poznanski was born on May 3, 1914, in  Cleveland , Ohio, the home of her mother, Sarah Auerbach. She was the youngest of sisters Mary and Helen, who both later emigrated to Israel. Her father was Jakob Poznanski, a businessman and Polish native who had come to the United States from Belgium. When Poznanski was still a baby, the family moved to  The Bronx , New York, where she was schooled at  Wadleigh High . Though not religious, she adopted the  Yiddish  name of Gitel. Her mother was active in the  women's suffrage movement  and in leftist politics.


Steed began a  BA  in banking and finance at  New York University , but embraced the  Greenwich Village  artistic and political life, often singing blues in nightclubs, and dropped out to take a job as a writer with the  Works Progress Administration .  Rafael Soyer  painted portrait of her at eighteen,  Girl in a White Blouse , (1932) which is in the collection of the  Metropolitan Museum of Art  in New York City, and she is the medusa-haired subject in Soyer's  Two Girls  1933 (oil on canvas) at the Smart Museum. In 1933 she met the painter Robert Steed (b.1903), whom she married in 1947.


Philosopher  Sidney Hook  persuaded Steed to return to NYU and in 1938 she completed her B.A. with honors in sociology and  anthropology , then studied as a graduate at  Columbia University  until 1940 as a Research Fellow in the Department of Anthropology under Professor  Ruth Benedict  whom she had met in 1937 and who in 1939 led Gitel Steed's first field experience among the  Blackfoot Indians  of  Montana . [ 3 ]   Benedict's  Patterns of Culture [ 4 ]  was published in 1934 and had become standard reading for anthropology courses in American universities for years, and Steed was influenced by Benedict's position in that book that, "A culture, like an individual, is a more or less consistent pattern of thought and action", and that each culture chooses from "the great arc of human potentialities" only a few characteristics which become the leading personality traits of the persons living in that culture. From 1939 to 1941, Steed undertook research for  Vilhjalmur Stefansson , the explorer and writer on Inuit life then planning a two-volume  Lives of the Hunters , on diet and subsistence; Steed worked on the South American Ona,  Yahgan , and the  Antillean  Arawak and Carib, and from this formative experience began a dissertation on hunter-gatherer subsistence (not finished until 1969, well after she had established her career). [ 5 ]


In 1944, after the  Nazi   holocaust  against the Jews was exposed, Gitel Steed set aside her anthropology and joined the Jewish Black Book Committee, an organization of the  World Jewish Congress  and other Jewish anti-Fascist groups. With a few peers, she participated during 1944 and 1945 in writing  The Black Book: The Nazi Crime Against the Jewish People , an exhaustive indictment of calculated Nazi anti-Jewish war crimes intended for submission to the  United Nations War Crimes Commission . Steed wrote "The Strategy of Decimation"  published in 1946 for the Jewish Black Book Committee.


Steed taught at  Hunter College  in New York 1945 and 1947. While teaching at  Fisk University  in 1946/1947 she researched the  Negro  in the United States and in Africa and was managing editor of the university's and the American Council on Race Relations' monthly summary of "Race Relations" in America. [ 6 ] [ 7 ]


In 1947–1949 she joined Dr.  Ruth Bunzel  in establishing the China group of Columbia's Research in Contemporary Cultures to study immigrant Chinese culture, primarily in New York City, from 1947 into 1949, working with migrants from the same community from China's  Kwantung  Provincial village,  Toi Shan . She undertook life histories, community self-analysis, and projective tests, then proposed an extended field project in the Toi Shan community to understand the interdependency in social and economic relations between migrants and their kinsmen at home.  Margaret Mead  and others joined these Columbia  comparative studies  of contemporary cultures and they were incorporated into Mead's "The Study of Cultures at a Distance," [ 8 ]


Steed planned "The Effects of Village Institutions on Personality in South China" and had funds granted for its continuation of her Chinese research in China. [ 1 ]  However the occurrence of the  Chinese Revolution  of 1948 scuttled the project.


Steadfastly committed to field study of institutional determinants of individual and social character, she took up the suggestion of  psychiatrist , Abram Kardiner, then associated with Columbia University's Department of Sociology, to pursue a similar study in India. [ 9 ] [ 10 ]  Shortly thereafter, Professor Theodore Abel, department chairman, appointed Steed Director of a two-year field project of research in contemporary India. [ 11 ]  Funding was received through a grant from the Department of the Navy. [ 12 ]  She assembled a research team of Dr. James Silverberg, Dr.  Morris Carstairs  of  Edinburgh University , and her husband Robert Steed, leaving for India in 1949, where there was added a small staff of Indian workers. They included Bhagvati Masher and Kantilal Mehta, who worked as interpreters; Nandlal Dosajh, a psychologist; [ 13 ]  N. Prabhudas, an economist who conducted the land use survey; and Jerome D'Souza as cook. In the second year of research, the team also included an Indian assistant, Tahera, as well as Americans Grace Langley and John Koos. [ 12 ]  Her preparations were aided by her friendship with Gautam Sarabhai, a Gujarati Indian she had met in New York who assisted her in learning  Hindustani .  She also trained in the use of a professional camera.


The research goals and procedures were ambitious; to  empirically  bring together interactions of individual, culture, community and institutions, relating real individuals, not merely statistical patterns, for functional-historical analysis of character formation at the village level [ 14 ] [ 15 ]  in the three settlements chosen:  Bakrana , a  Hindu  village in  Gujarat ; Sujarupa, a Hindu hamlet in  Rajputana ; and Adhon, a predominantly  Muslim  village in the  United Provinces . Bakrana was a farming economy in fertile flatlands, exclusively Hindu and with an active  caste system , largely untouched by the former  British rule  or by land reform changes current then in India. Sujarupa hamlet was a single-caste community in the upland valleys. Adhon was controlled by pro-independence Muslims, with more occupational castes and subgroups than Bakrana, with religious minorities.


Steed returned to the United States in December 1951 with more than 30,000 pages of handwritten notes and some thousands of ethnological photographs, but infected with  malaria , and shortly after her return she also developed  diabetes  which was particularly difficult to control and frequently put her in hospital. In addition, she had had  pituitary cancer  for over thirty years. Illness impaired her later career so that she was unable to receive her  doctorate  until 1969, 8 years before her death. In 1963, however, Conrad Arensberg wrote "her reputation and accomplishments are such as to make her lack of a PhD of little moment for her standing in the profession". [ 16 ]  Her reputation also rests on her unpublished notes; the thousands of pages of interviews, observations, projective test results, life histories, and villagers' paintings, most of which are now in the special collections of the University of Chicago Libraries.


During the eleven years after returning from India and taking up a position at Hofstra College (now  Hofstra University ) in 1962 where she continued to her death in 1977, Steed had no university affiliation and promoted her work through seminars and lectures at  Columbia University ,  University of Chicago , and the University of Pennsylvania. In 1953, Steed participated in a Social Science Research Council Conference on Economic Development in Brazil, India, and Japan, analyzing  Dr. Morris Opler's  "Cultural Aspects of Economic Development in Rural India", then later that year, 1953/4, she analyzed "The Individual, Family, and Community in Village India" in Columbia University's Department of Sociology graduate seminar on the psychodynamics of culture, chaired by  Abram Kardiner . In 1954 Steed lectured on "The Child, Family and Community in Rural Gujarat" for the University of Chicago  Seminar on Village India . The lectures and discussions are recorded in the archive. She presented in India symposia at meetings of the  American Anthropological Association , and the  Social Science Research Council .


Her one publication of note during this period was a chapter "Notes on an Approach to a Study of Personality Formation in a Hindu Village in Gujarat", [ 17 ]  illustrating cultural and institutional influences on the personality of a single  Rajput  landowner, [ 18 ]  for a volume  Village India: studies in the little community [ 19 ]  edited by Alan Beals and Dr. McKim Marriott, published in 1955; [ 20 ]  Steed's chapter has been held up as a model for the treatment of personality problems and culture in India. [ 21 ]  This, and the presentations she made at conferences assisted her in delimiting her doctoral thesis  Caste and Kinship in Rural Gujarat: The Social Use of Space .


During these eleven years she gave birth to her son, Andrew Hart (b. 1953), and taught English at the  Jefferson School , a Manhattan private school favored by the political left. Gitel and husband Robert Steed opened the doors of their house on West 23rd Street to visitors who included Ruth Bunzel,  Sula Benet ,  Vera Rubin ,  Stanley Diamond ,  Alexander Lesser ,  Margaret Mead , and Conrad Arensberg.


In 1970 Steed revisited  Bakrana , its population then doubled since her last visit, to observe the impact of the transforming politics in India.


Edward Steichen , Director of the Department of Photography of the Museum of Modern Art, said Steed's photographs of Indian villagers, which though taken for the anthropological record and used as illustrations in varied lectures and presentations, ranked "with first-rate human interpretations by professional photographers." [ 22 ]  In 1953, Steichen mounted  Always the Young Strangers  exhibition at  MoMA  in honour of  Carl Sandberg's  75th birthday and included Gitel Steed's photos, six of which are in the Museum's permanent photographic collection. Steichen again used her pictures in the Museum's world-touring blockbuster,  The Family of Man  exhibition and book. Her photographs were republished in the  New York Times , and featured in the  St. Louis Post Despatch . While at Hofstra University, her photographic work was exhibited as part of the university's "Focus on India" presentation in 1962, and in 1963 Hofstra showed Steed photographs of Hindu and Muslim villagers. That same year Steed held the exhibition  Child Life in Village India  at the New Canaan Art Association Gallery in Connecticut and another,  Cradle to Grave in Village India  at the Hudson Guild Gallery in New York. In 1967 Vincent Fresno's  Human Actions in Four Societies  used a selection as illustrations. [ 1 ]


Steed died in the night of September 6, 1977, evidently from a heart attack, at the age of sixty-three. She was survived by her husband and supporter for thirty years, artist Robert Steed, and by her son, Andrew.


The Gitel P. Steed papers 1907–1980 are archived in the University of Chicago Library and extend to approximately 13 linear metres (43 feet) of material. Most is data from her Columbia University Research in Contemporary India Field Project of 1949–1951 collected from three villages in western and northern India; extensive life histories of informants, psychological tests, typed notes, field notebooks, photographs, genealogies, histories, transcripts of interviews, and art work, mostly watercolours, by both researchers and child and adult villagers. These are joined by records of lectures and other publications relating to the India Project by Steed and by other scholars. Also held is data from Steed's previous fieldwork project among Chinese immigrants in New York City. The collection was given to the University of Chicago Committee on Southern Asian Studies by Robert Steed in 1978 and conveyed to the University of Chicago Library in 1984. Prior to their arrival, James Silverberg and McKim Marriott put the papers a preliminary order reflected in the collection's current organization. The collection was augmented by Robert Steed in 1985 and 1989, and by McKim Marriott and James Silverberg in 1994.  [3]


Stratified reproduction  is a widely used [ 1 ]   social scientific  concept, created by Shellee Colen, that describes imbalances in the ability of people of different races, ethnicities, nationalities, classes, and genders to reproduce and nurture their children. [ 2 ]  Researchers use the concept to describe the "power relations by which some categories of people are empowered to nurture and reproduce, while others are disempowered," as  Rayna Rapp  and  Faye D. Ginsburg  defined the term in 1995. [ 3 ]


Globally, women are confined to different societal standards on reproduction. The ability to choose whether women want to become pregnant is not available to all women.  Contraception  and  abortions  can be illegal or difficult to obtain depending on location or  socioeconomic status . Women's experience of child birth has varied from required minimum number of children a mother must birth and honors for overachieving the set minimums to a restricted the number of children per household. In a broader sense, stratified reproduction asserts that certain categories of people are encouraged and coerced to reproduced while others are systematically discouraged to do so. The capacity to control one's reproductive choices is unequally distributed among race, sexual orientation, gender, class and socioeconomic status. [ 4 ]  Stratified reproduction also extends beyond the aspect of reproduction to the extent of conception, contraception, prenatal medical care, childcare, and the mother's role in their child's life. [ 5 ]


In 1984, Shellee Colen coined the term "stratified reproduction" when studying West Indian childcare workers in New York City, who typically worked for wealthier white families. Colen highlighted differences between white and West Indian mothers’ ability to choose how they each care for their children. The white mothers hire a nanny to carry out the routine tasks of childcare while the West Indian mothers forgo the ability to raise their children so that they can financially support them. Colen drew the conclusion that child birth and childcare is experienced, valued, and rewarded differently depending on a mother's socioeconomic status and availability of resources. [ 2 ]


Since the emergence of the term stratified reproduction, researchers have applied its concepts to analyze the different effects of varying social factors on reproduction and childcare.  Rayna Rapp  and  Faye D. Ginsburg  pioneered the application of stratified reproduction to different societies to emphasize the variation to which women experienced reproduction and childcare. In Rapp and Ginsburg's book,  Conceiving   the New World Order: The Global politics of Reproduction , they discuss several societies that limited women's choice on reproduction and childcare due to socioeconomic factors. [ 3 ]  They touch on Shellee Colen's research on West Indian nannies in New York and how they are unable to participate in their own child's childcare, because they must immigrate to America to find work to support their family. [ 3 ]  They also include Gail Kligman's research on abortion bans in  Romania  under  Ceausescu ’s rule. [ 6 ]  State policy required the Romanian women to birth at least four children in hopes of increasing the population for a more efficient socialist country. They also discuss China’s limit on the maximum number of children per household, and low-income African American women’s struggle to obtain proper contraceptives and abortions. [ 3 ]  Rapp and Ginsburg concluded that “global and local socioeconomic relations that form the context for stratified reproduction, whereby ‘some categories of people are empowered to nurture and reproduce, while others are disempowered’”, and that cultural ideologies and state policies reinforce the stratified reproduction implanted by socioeconomic factors.


The scope of use of the stratified reproduction framework is not limited to women’s access to contraceptives or lack thereof. Researchers are applying stratified reproduction to the health of the mothers and children. Infertility has also been linked to the effects of stratified reproduction. Scarce financial resources deters mothers from being able to reach effective medical services to help prevent infertility. [ 7 ]


Infertility is just one aspect of stratified reproduction. Although it is estimated that 186 million people worldwide are affected by infertility, technology can be able to assist those who are infertile. [ 8 ]  In-Vitro-Fertilization (IVF) is one assisted reproductive technique (ART) that is used. IVF was developed over 30 years ago to help women with blocked or damaged fallopian tubes. IVF has helped many couples achieve their dreams of having a child. However, IVF is extremely expensive and/or inaccessible to many globally. In Central and Southern Africa "two-thirds of infertile women have diagnoses of tubal blockage attributable to sterilizing RTIs [Reproductive Tract Infections]" which is exactly what IVF was developed for. [ 9 ]  The high costs and inaccessibility keep infertility as a major aspect of stratified reproduction. According to a study done by Marcia C. Inhorn and Pasquale Patrizio, regions such as South Asia, sub-Saharan Africa, the Middle East and North Africa, Central and Eastern Europe and Central Asia have high infertility rates. [ 8 ]  While infertility is a global phenomenon, other issues within those regions play a role in their high infertility rates.
Secondary infertility, being unable to conceive after a previous pregnancy, is the most common form of infertility in women. [ 8 ]  Typically secondary infertility comes from RTIs. In countries where abortions are illegal, women will choose to have unsafe abortions. These unsafe abortions can lead to RTIs and secondary infertility if left untreated. Studies show that in places where laws are lifting the ban on abortions, secondary infertility rates are decreasing. [ 9 ]


Racial disparities and socioeconomic status also play a role in infertility as well as the reported use of medical services for infertility. Data from the National Survey of Fertility Growth (NSFG) showed that infertility rates for black (19.8 percent) and Hispanic women (18.2) were much higher than those rates for white women (6.9 percent).The same study revealed that although women of color experience higher infertility rates, they reported having not received medical services for infertility at higher rates than their white counterparts. [ 10 ]  Socioeconomic status also provides barriers for women who do not have the flexibility to take off work and schedule appointments that higher socioeconomic status women do. [ 10 ]  Without public or even insurance company funding for these ARTs, this suggest that those in a higher socioeconomic standing should be able to reproduce, while those who cannot afford these treatments should not have the same ability to do so. This notion is furthered by policies such as the welfare reform act of 1996 which denies benefits to children who are born to mothers on welfare. [ 4 ]  However, race and class disparities in infertility treatment remain even in states that have mandated infertility insurance coverage suggesting that the issue of stratified infertility options go beyond political policies.


Adoption is another infertility option that hosts many barriers to underrepresented populations. Cost is one factor that is a barrier for people with a low SES status. There is also a devaluation of children of color within the adoption system. The demand for white children is higher than that for children of color, thus leading some adoption agencies to charge more to adopt white children. This practice suggests that white children are of higher value than children of color. [ 4 ]


As there is a continual expansion of reproductive technologies, there is also increasing deficits in the access and utilization of these technologies due to stratified reproduction. Barriers achieving equal access to these reproductive technologies include high costs, lack of adequate healthcare or no healthcare, restrictive policies, lack of transportation and the lack of autonomy given to women to make their own reproductive decisions. [ 4 ]


Sheoran uses Shellee Colen's 'stratified reproduction' conceptual framing to propose that contraception is experienced hierarchically in places like India. Sheoran, when writing of Emergency Contraceptive Pills in India writes, 'ECPs in India thus make visible the reality of ‘stratified contraception,’ even as these technologies make inviting claims of eradicating stratification by providing all women with access to these pills at the local pharmacy'(pg. 250). [ 11 ]


Sterilization is a relatively permanent form of contraception that can be used to give women reproductive control; however, this form of contraception has a history of blatant misuse. Sterilization was used to reinforce the social hierarchy where wealthy, white families were genetically superior to other groups of people. In this hierarchy, people of color, people with mental illnesses, criminals, those on welfare, single mothers and addicts were all seen as genetically inferiors; therefore justifying forced sterilization for the common good. The main target of forced sterilization were poor women of color. [ 12 ]


In more recent history, there is still subtle and covert forms of coercion for certain groups to undergo sterilization. Sterilization rates still remain unequal between poor women of color and their white counterparts with Black and Native American women being twice as likely to have received a tubal sterilization. This data is found to be surprising taking into consideration that women of color are less likely to receive reproductive care or have health insurance to cover the costs of this procedure. A few explanations of this discrepancy is negative stereotypes of women of color as poor mothers and assuming women of color cannot afford children without being on welfare. These assumptions often lead to coercion and more invasive surgeries for reproductive issues that lead to sterilization. [ 12 ]  With women of color still at the forefront of this misuse of sterilization, the prison system has become a large target for coerced sterilizations. It was discovered that over 150 women were forcibly sterilized  in prison between 2006 and 2010 because these women were deemed likely to return to prison. Even though sterilization was a costly procedure, physicians claimed that it would be better to pay for the procedure than pay for the welfare of these women's children. [ 13 ]


Ethnicity and race also play a role in stratified reproduction. Western media often focuses on the infertility of middle-class white women, to the detriment of poor and nonwhite women. [ 14 ]  Race and ethnicity are common tools used to justify reproductive injustices and  health disparities  seen throughout the United States. [ citation needed ]


Recent scholarship has investigated the history of conflict around Latinas and fertility in the United States. These stories provided evidence that the United States had funded forced sterilization of Latino people and other ethnic groups. [ citation needed ]  In their article, Elena R. Gutiérrez and Liza Fuentes study two communities, Puerto Rican women in Puerto Rico and New York and Mexican-origin women in Los Angeles. [ 15 ]  Once Puerto Rico became an American colony in 1898, people [ who? ]  began to talk about Puerto Rico being overpopulated. By 1965, over 34% of mothers aged 20–49 had been sterilized. [ 15 ]  Not all women chose to be sterilized. [ 15 ]  Many of these women were used for contraceptive testing without their knowledge. [ 15 ]  Mexican-origin women were another community that experienced forced sterilization. Some women were forced into nonconsensual sterilizations, including as they were giving birth. [ 15 ]  Scholar Leo Chavez argues that these sterilizations came from the idea that Latinos are over-populating the U.S. [ 16 ]


In his article, Leo Chavez discusses Latino fertility in the United States. He writes that their presence promoted anti-immigration sentiment and advertising suggesting that they should leave the United States and that their fertility was not welcome in the country. [ 16 ]  Puerto Ricans, such as those discussed in the article by Gutiérrez and Fuentes, were a part of this larger Latino community that was being targeted. In Chavez's article, he collects data to discuss fertility rates among Latinas, showing that, though Latina women were more fertile than their non-Hispanic white counterparts, they had fewer lifetime sexual partners. [ 16 ]


Nearly one in four African-American women live below the poverty line, which greatly increases the risks associated with bearing children. [ 17 ]  Black women are two and a half times more likely to die during pregnancy, and their children are two times more likely to die as infants. [ 18 ]  Many [ who? ]  attempt to view this issue as a biological issue of African-American women; however, black women residing in other countries have less reproductive complication than their American counterparts. [ citation needed ]  Black women are less likely to be given medical advice, to be warned of possible medical complications, and to receive helpful prenatal therapies. [ 19 ]   This differential treatment from medical health professional leads to more birth complications, adverse birth outcomes and fetal death thus contributing to the system of stratified reproduction. [ 19 ]


Residential segregation may indirectly harm health through harmful living environments and limited access to resources. Segregated communities often are characterized by more crime, greater pollution, higher population densities, more poverty,  and fewer and lower-quality services, leading to infant mortality. [ 19 ]  This includes forms of environmental injustice, which incorporates the unfair plotting of landfill facilities and the deliberate targeting of minority and low-income communities as repositories for hazardous waste sites. [ 20 ]  Even though residential segregation affects various minority groups, in the United States there are stark health discrepancies between black woman and their white counterparts. Flint, Michigan is a predominately black area that exemplifies the harmful impact low environmental quality can have on healthy reproduction: The  Flint water crisis  decreased fertility rates by 12 percent and raised infant mortality by 58 percent among Flint residents. [ 21 ]


More recently, there has been a closer look into how the system of stratified reproduction impacts the LGBTQ+ community. Stratified reproduction within the reproductive field of medicine feeds into a political economy that does not include a  right to health , but a right to purchase health care if one can afford it and is deemed worthy of these biomedicines. [ citation needed ]  States such as Arizona and Mississippi have recently seen legislative attempts to allow health care services to deny care to LGBTQ people; these stratifications of access to care also deny LGBTQ people the same possibilities for family planning and formation. [ 22 ]


Sudanese kinship , also referred to as the  descriptive system , is a  kinship system  used to define  family . Identified by  Lewis Henry Morgan  in his 1871 work  Systems of Consanguinity and Affinity of the Human Family , the Sudanese system is one of the six major kinship systems ( Eskimo ,  Hawaiian ,  Iroquois ,  Crow ,  Omaha  and Sudanese). [ 1 ]


The Sudanese kinship system is the most complicated of all kinship systems.  It maintains a separate designation for almost every one of Ego's kin, based on their distance from Ego, their relation, and their gender. Ego's father is distinguished from Ego's father's brother and from Ego's mother's brother. Ego's mother is similarly distinguished from Ego's mother's sister and from Ego's father's sister.  For cousins, there are eight possible terms.


The system is named after the peoples of  South Sudan .  The Sudanese kinship system also existed in ancient  Latin-speaking [ 2 ]  and Anglo-Saxon [ 3 ]  cultures.  It exists today among present-day  Arab , Turkish, [ 4 ]  and  Chinese  cultures. It tends to co-occur with  patrilineal  descent, and it is often said to be common in complex and stratified cultures. [ 5 ]


Balkan kinships such as  Bulgarian ,  Serbian , and  Bosniak  follow this system for different  patrilinear  and  matrilinear  uncles but collapse mother's sister and father's sister into the same term of "aunt" and  Croatian  and  Macedonian  further collapse the offspring of the uncles into one term.


Similarly,  Finnish  kinship terms separate patrilinear and matrilinear uncles but not aunts, while making no distinctions between first cousins but giving a separate term for second cousins. Further distinctions (some much more common than others) can be made between a patrilinear or matrilinear grandson/granddaughter, niece/nephew, grandfather/grandmother and others, by using compound words. An interesting feature is the presence of many unique words originating from  Proto-Uralic  and  Germanic  languages to describe  affinal kinships  such as, but not limited to, the brother of a spouse (lanko), mother-in-law (anoppi) or even the husband of a daughter (vävy).


On the opposite side,  Chinese  adds an additional dimension of relative age. Ego's older siblings are distinguished from younger, as are those of Ego's parents. One must specify whether older (e.g.   Mandarin  哥哥  gēge ) or younger (e.g. Mandarin 弟弟  dìdi ). Similarly, a term for "uncle" or (in at least in some  varieties of Chinese , including Mandarin) even "father's brother" does not exist without circumlocution; the speaker must either specify "father's older brother" (e.g. Mandarin 伯伯  bóbo ) or "father's younger brother" (e.g. Mandarin 叔叔  shūshu ). This does not apply to maternal uncles.


A  teip   (also  taip ,  tayp ,  teyp ;  Chechen  and  Ingush : тайпа, romanized:  taypa   [ˈtajpə] ,  lit.   family ,  kin ,  clan ,  tribe [ 1 ] ) is a  Chechen  and  Ingush   tribal  organization or  clan , self-identified through descent from a common  ancestor  or geographic location.  It is a sub-unit of the  tukkhum  and  shahar . There are about 150 Chechen and 120 Ingush teips. Teips played an important role in the socioeconomic life of the Chechen and Ingush peoples before and during the  Middle Ages , and continue to be an important cultural part to this day.


Common teip rules and some features include: [ 2 ]


Teips being sub-units of tukkhums, members of the same teip are traditionally thought to descend from a common ancestor, and thus are considered distant blood relatives. Teip names were often derived from an ancestral founder. [ 3 ]  As is also true of many other North Caucasian peoples, traditionally, Chechen and Ingush men were expected to know the names and places of origin of ancestors on their father's side, going back many generations, with the most common number being considered 7. [ 3 ]  Many women also memorized this information, and keener individuals can often recite their maternal ancestral line as well. [ 3 ]  The memorization of the information serves as a way to impute clan loyalty to younger generations. [ 3 ]  Among  peoples of the Caucasus , traditionally, large scale land disputes could sometimes be solved with the help of mutual knowledge of whose ancestors resided where and when. [ 3 ]


A teip's ancestral land was thus held as sacred, because of its close link to teip identity. It was typically marked by clan symbols, including the clan cemetery, tower, and sanctuary. [ 3 ]  Land being scarce in mountainous Ingushetia and Chechnya, after the feudal system was overthrown, each teip claimed a definite area of land. [ 4 ]  Land boundaries were marked by stones with specific marks pointing to a local place of worship. [ 4 ]  While at first land was owned collectively, individual cultivation ultimately became the norm. [ 4 ]  In old Chechen and Ingush tradition, women were allowed to own land. [ 4 ]  The vehement Ingush and Chechen opposition to Soviet  collectivization  has been explained by the threat it posed to the traditional customs of land allotment. [ 4 ]