Midwifery  and obstetrics are different but overlap in medical practice that focuses on  pregnancy  and labor. Midwifery emphasizes the normality of pregnancy along with the reproductive process. Classical Antiquity saw the beginning of attempts to classify various areas of medical research, and the terms gynecology and obstetrics came into use. The  Hippocratic Corpus ,  a large collection of treatises attributed to  Hippocrates , features a number of gynecological treatises, which date to the classical period.


During the era of Classical Antiquity, women practiced as doctors, but they were by far in the minority and typically confined to only gynecology and obstetrics.   Aristotle  was an important influence on later medical writers in Greece and eventually Europe.  Similar to the writers of the  Hippocratic Corpus , Aristotle concluded that women's physiology was fundamentally different from that of men primarily because women were physically weaker, and therefore more prone to symptoms caused in some way by weakness, such as the theory of  humourism .  This belief claimed that both men and women had several "humours" regulating their physical health, and that women had a "cooler" humour. [ 1 ]  The  Hippocratic Corpus  writers indicated that men were more rational than women, and that women's physiology made them susceptible to problems that would cause symptoms of irrationality. [ 1 ]  Continuing with this assumption that men were more rational, men dominated the profession of physicians, an occupation requiring rational research, and for which they believed women were not suited.


This did not stop women from becoming physicians.  Philista  was a popular professor of medicine who delivered lectures from behind a curtain, to prevent her beauty from distracting her students. [ 2 ]  In ancient Greece, there was also an opportunity for midwives to receive some further medical training, to become a doctor-midwife, called in the Hellenistic, Roman and Byzantine eras an  iatromea  (ιατρομαία). [ 3 ]


Women doctors may have offered specializations beyond gynecology and obstetrics, but there is not enough information to know how frequently. As obstetricians and gynecologists, they appear to have been numerous. The  Code of Justinian  presumed women doctors to be primarily obstetricians. The first medical text known to be written by a woman is by  Metrodora ,  Concerning the Feminine Diseases of the Womb . [ 4 ]


During  Classical Antiquity , anyone could be trained as a doctor at one of the many medical schools/hospitals, the  Asclepeieon . Training involved mainly practical applications as well as forming an apprenticeship to other doctors. During the Hellenistic era, the  Library of Alexandria  also served as a medical school, where research and training would take place on the body of the diseased. It also appears that the children, male or female, of famous doctors, would also follow the medical profession, continuing the family tradition. For example,  Pantheia, who was the wife of a physician, became one herself, a pattern also seen in the careers of Aurelia Alexandria Zosime and Auguste. Auguste received recognition as a chief doctor of her city, a title her husband also received. Metilia Donata was prominent enough to commission a large public building in Lyon.  Anthiochis of Tlos , the daughter of a prominent physician, Diodotus, was recognized by the council of Tlos for her work as a doctor and had a statue of herself erected. She was also a widely discussed expert cited by  Galen  and others.  Aspasia  is quoted extensively by  Aetius  on gynecology. [ 5 ]


This Greco-Roman approach differs greatly from other ancient civilizations, where women's role as medical specialists concerning gynecology and obstetrics was apparently unquestioned. Medical schools attached to temples in ancient Egypt were numerous, including well-known medical schools for women at  Heliopolis  and  Sais , where women are also believed to have been the professors. [ 2 ]


Hippocrates  was the first to use the term  cancer  to describe the hard lesions occasionally found in women's breasts. He reasoned that the lesions were caused by problems with the woman's uterus and menstrual cycle. Symptoms of these lesions were believed to be pain, appetite loss, bitter taste, and confusion. [ 6 ]  Hippocrates urged against surgery as a treatment for breast cancer because he considered it harmful and found that the prognosis was much better for women who did not have the lesions removed or treated. In his later work  Diseases of Women,  Hippocrates furthers the list of late-stage cancer symptoms by including deliria, dehydration, dry nipples, loss of sense of smell, and shallow breathing. [ 7 ]


Galen  considered breast cancer to be a result of excess black bile in the body, referencing to Hippocrates' theory of the  humoral theory of diseases . He hypothesized that a women's menstrual period was a method of removing black bile from the body. This idea fit his observation that it more common for women in menopause and pre-menopause to develop breast lesions. Unlike Hippocrates, Galen encouraged surgical removal of tumors and even prescribed special diets and purgation to rid the body of excess black bile. [ 7 ]


Aristotle  formulated early tests for infertility by placing scented cloth in a woman's vagina for an extended amount of time and determining whether the aroma came out of the mouth or if the eyes or saliva was colored. This test determined whether or not the woman's semen passes were open or closed. [ 8 ]   Hippocrates  formed a similar test by observing whether a scent would pass through a woman's body out of her mouth when the smell was produced between her legs while she was wrapped in a blanket. Hippocrates further tested for infertility by putting red stone in a woman's eyes and determining if it penetrated through. [ 8 ]


During antiquity, there was no profession equal to that of our modern day nurse. No ancient medical sources discuss any sort of trained nursing personnel assisting doctors. However, many texts mention the use of slaves or members of a doctor's family as assistants. [ 9 ]  The closest similarity to that of a nurse during antiquity was a midwife.  Midwifery  flourished in ancient civilizations, including Egypt, Byzantium, Mesopotamia, and the Mediterranean empires of Greece and Rome.


There were doctors within the Greco-Roman world who wrote favourably of midwifery.  Herophilus  wrote a manual for midwives, which advanced their status. This was followed by the work of the Greek  Soranus of Ephesus  (98–138 AD), who was widely translated into Latin, [ 10 ]  and  Galen . Soranus was an important gynecologist and is credited with four books describing the female anatomy. He also discussed methods to deal with difficult births, such as using forceps. [ 11 ]  He also outlined a series of criteria for woman to be an eligible midwife. He wrote:


A suitable person…must be literate to be able to comprehend the art through theory too. She must have her wits about her so that she may easily follow what is said and what is happening. She must have a good memory to retain the imparted instructions (for knowledge arises from memory of what has been grasped). She must love work, to preserve through all vicissitudes (for a woman who wishes to acquire such vast knowledge needs manly patience).


The most qualified midwife would be trained in all branches of therapy.  She should be able to prescribe hygienic regulations for her patients, observe the general and individual features of the case, give advice by recalling from previous knowledge what medical decisions would work in every case and to be reassuring to her patients. It is not necessary for her to have had a child to deliver another woman’s child, but it is good if she has been in labor to enhance sympathy with the mother.


To obtain good midwifery habits, she will be well disciplined and always sober, have a quiet disposition sharing many life secrets, must not be greedy for money, be free of superstition to not overlook salutary measures, keeping her hands soft by staying away from wool-working as this may harden her hands and use ointments to acquire softness.  She too needs to be respectable, the people of the household will have to trust her within their household, may not be handicapped in the performance of her work.  Long and slim fingers with short nails are necessary to touch deep-lying inflammation without causing too much pain.  Midwives that acquire of all these will be the best midwives. [ 12 ]


This detailed instruction on midwives served as a sort of textbook and makes evident the well-respected role that midwives filled in society.


Women practiced birth control in antiquity mainly through their knowledge of plants and herbs. Their knowledge was transmitted by herders who observed sterility of their livestock when exposed to certain plants. Knowledge of birth control was also transmitted by word of mouth, mainly originating from knowledgeable midwives. Midwives knew how to identify necessary plants, how to administer them, and most importantly,  when  to administer them in relation to the last menstruation or coitus. [ 13 ]


A very popular plant used for birth control by the Greeks was  Silphium . It is a giant fennel-like herb which was filled with a pungent sap and offered a rich flavor. The plant was so widely used that it appeared on a Cyrenian coin as a woman touched the plant with one hand and pointed to her genitals with the other. [ 13 ]  The demand for the plant was so great that by the fourth century, it had gone extinct. It is believed that the heart shape originated from the seed of this plant as they are the same shape and the plant was associated with love, romance, and sexuality. [ 14 ]


Although Silphium was most popular, there were many other plants and herbs used. Another plant used was  pennyroyal , an  abortifacient . [ 15 ]  Although toxic, pennyroyal was consumed in small dosages in tea because it contained the abortive substance pulegone. [ 16 ]  A medical document dating back to 1500 BC in Egypt includes a list of substances used as birth control. One substance involved making a paste from acacia gum, dates, fiber, honey, and other unidentified plants to create a sort of spermicide. [ 13 ]  Early physicians  Galen  and  Dioscorides  believed that women would consume willow and pomegranate kernels to prevent pregnancy as well. [ 16 ]


Soranus of Ephesus  advocated for the application of ointments made of old olive oil, honey, cedar resin, and white lead on the cervix in order block the opening to the uterus. However, Soranus believed birth control was most effective when oral contraceptives were combined with certain procedures. Soranus recommended that women should avoid having intercourse during their fertile period in their cycle, as well as avoid deep penetration. [ 16 ]  After intercourse, women were urged to squat, sneeze, and cleanse the vagina before drinking something cold. If these combined practices failed in the prevention of pregnancy, recipes including small amounts of Cyrenaic juice, diluted wine, leukoion, and white pepper were prescribed to induce abortion. [ 16 ]


According to the Hippocratic Corpus, there were oral alternatives used to induce abortion such as chaste, tree, copper, and Ferula species. [ 14 ]  Plato explored the control that midwives perhaps had during this process:


And furthermore, the midwives, by means of drugs [149d] and incantations, are able to arouse the pangs of labor and, if they wish, to make them milder, and to cause those to bear who have difficulty in bearing; and they cause miscarriages if they think them desirable.


There were many theories used to determine whether a woman was pregnant during antiquity. A popular method involved examining the vessels of her breasts. A second method involved sitting a woman on a beer and date mash covered floor and using a proportionality equation according to the number of times she vomits. Another method included inserting an onion into a woman's vagina and determining whether or not it could be smelled from her breath. [ 13 ]  Although there is little evidence as to whether or not any of these methods were confirmed medical procedures or if they were just folklore.


Hospitals did not exist during antiquity so delivery took place in the home of the expectant mother with a midwife and other assistants to the midwife. Religion played a major role during labor and delivery. Women called upon  Artemis , a goddess with the ability to bring new life into the world as well as the ability to take it away. Though she remained a virgin herself, it was said that she witnessed the pain of her mother during the birth of her brother,  Apollo , and immediately assumed the position of midwife.  If a woman died during childbirth, her clothes were taken to the temple of Artemis due to the fact the woman's death was attributed to her. [ 17 ]  If the birth was successful, the mother would make an offering of thanks by sacrificing some of her clothes to the goddess as well. [ 18 ]


Herbs and other plants were used heavily in the delivery process, a practice also linked to religious belief.  For example, a drink sprinkled with powdered  sow ’s  dung  was given to relieve labor pain, and  fumigation  with the fat from a  hyena  was thought to produce immediate delivery. [ 19 ]  Most of these practices had little to no medical efficacy, but they did probably provide some  placebo  effect. Despite the attempt to use science in advancing medical knowledge, the experimentation and teachings of the  Hippocratic Corpus  were not necessarily more effective than the traditional customs of midwifery. For example, the Hippocratic writers believed that the womb could move out of place and cause health problems, and the prescribed treatment was to coax the displaced womb back into place using sweet-smelling herbs. [ 20 ]


Soranus described three main stages of pregnancy: conception, which regarded keeping the male seed within the womb;  pica , which occurred 40 days into pregnancy and included symptoms of  nausea  and  cravings  for extraordinary foods.  During this phase women were also instructed to exercise and sleep more to build up strength as preparation for the labor process. The final stage of pregnancy was described as the labor and the process of delivery.  In preparation for labor, the woman was advised to bathe in wine and sweet-water baths to calm her mind before delivery.  Her belly was then rubbed with oils to decrease the appearance of stretch marks, and her genitals were anointed with herbs and injected with softeners such as goose fat. [ 19 ]


The role of the midwife was very important during the process of childbirth and Soranus described her role in great detail.  For example, the midwife was to have certain tools to ensure a safe delivery, including: clean olive oil, sea sponges, pieces of wool bandages to cradle the infant, a pillow, strong smelling herbs in case of fainting, and a birthing stool. [ 19 ]  A  birthing stool  is a chair from which the seat has been removed.


The midwife would ready her supplies as labor began. During the labor process, the mother would lie on her back on a hard, low bed with support under her hips. Her thighs were parted with her feet drawn up. Gentle massage was implemented to ease labor pains as cloths soaked in warm olive oil were laid over her stomach and genital area. Against the woman's sides were placed hot compresses in the form of warm oil-filled bladders. [ 19 ]


During the actual birth, the mother would be moved to the birthing stool, where she was seated or would  squat  on two large bricks with a midwife in front of her and female aides standing at her sides.  In a normal headfirst delivery, the  cervical opening  was stretched slightly, and the rest of the body was pulled out. Soranus instructed the midwife to wrap her hands in pieces of cloth or thin  papyrus  so that the slippery newborn did not slide out of her grasp. [ 19 ]


A widely cited myth claims that the word "caesarian" possibly derives from the ancient Roman ruler  Julius Caesar , because it was believed that Caesar was delivered through this procedure. [ 21 ]  The oldest reference to this myth is a passage from the  Suda , a 10th-century  Byzantine  encyclopedia. The myth is a misinterpretation of a passage from  Pliny the Elder 's  Natural History , which mentions a "Caesar" (one of the ancestors of Julius Caesar) being cut from his mother's womb. [ 22 ]  This practice is probably much older than Julius Caesar, and " C-sections ", as performed by the Romans, were done to rescue the baby from a dying or already dead mother, and were performed post-mortem. [ 23 ]  The fact that Julius Caesar's mother  Aurelia Cotta  lived for decades after Caesar's birth makes this etymology highly unlikely. [ 24 ]  Pliny mentions another more widely accepted possibility for the etymology of the word “caesarian”, claiming that it derives from the Latin word  caedere , meaning “to cut”. [ 21 ]


Rabbinical discussions recorded in the  Mishnah  suggest that  Jews  in the Roman period may have successfully practiced caesarians on living mothers who were not in danger of dying. [ 25 ]   Greeks  and  Egyptians  did not perform C-sections, either post-mortem or on living mothers. [ 25 ]  However, Greeks would have had at least some knowledge of the Caesarian operation and the procedure involved. The Greek god  Aesclepius  was fabled to have been extracted from his mother's womb through this procedure. [ 21 ]


Other than the evidence of Jews practicing C-sections in antiquity (very little in ancient Rome, even less in ancient Greece), not much more evidence exists regarding Caesarian-operation birth. One reason could have been that C-sections were not performed very often because of medical complications or superstitions surrounding C-sections. In early Christian Rome, C-sections were almost non-existent. [ 25 ]  Loss of skill is a possibility for the lack of C-sections. Infant mortality rates were high in antiquity, so C-sections certainly could have been useful. However, early Christian doctors could have disregarded C-sections as a socially acceptable operation because of religious beliefs. Disease, a perceived need for secrecy, and social discouragement could have also been factors that lead to the decline in C-sections among early Christians in Rome. Almost no evidence exists for C-sections in the Christian world until the 10th century. [ 23 ]


The lack of education for women and the social norm that women remained in the private sphere of life (as opposed to public) is theorized to also have contributed to a shortage of C-sections. [ 23 ]


Mortality was quite high in antiquity due to a few factors: a lack of sanitation and hygienic awareness, no understanding of  micro-organisms , and a dearth of effective drugs. In the context of childbirth, maternal and infant mortality were exponentially raised compared to modern standards. This resulted from the toll childbirth took on women, and the increased risk of infection following labor.


Maternal mortality figures are available only through comparison. Maternal mortality is thought to be comparable with figures for similar, but much later, societies with more surviving records, such as eighteenth-century rural England, where maternal mortality averaged 25 per 1,000 births. [ 26 ]


The question of infant mortality in antiquity is complicated by infanticide and exposure, neither of which reflect on medical ability during the period. The former does this through intentional death of the child, and the latter through abandonment, and possible death.  These reflect instead on social conditions and norms. While valuable, this is not the information sought, and scholars having painstakingly attempted to eliminate the 'noise' from their inquiries. [ 27 ]


Much like maternal mortality, it is difficult to construct actual figures of the infant mortality rate in antiquity, but comparisons have been made between ancient societies and modern non-industrialized societies.  The figures suggest that they are comparable with those of modern industrialized societies to put them in perspective.  While infant mortality is less than 10 per 1,000 in modern industrialized societies, non-industrialized societies display rates from 50 to 200+ per 1,000.  Scholarship using model life tables and assuming life expectancy at birth of 25 years produces the figure of 300 per 1,000 for Roman society. [ 26 ]


In  anthropology ,  kinship  is the web of social relationships that form an important part of the lives of all humans in all societies, although its exact meanings even within this discipline are often debated. Anthropologist  Robin Fox  says that the study of kinship is the study of what humans do with these basic facts of life –  mating ,  gestation ,  parenthood ,  socialization ,  siblingship  etc. Human society is unique, he argues, in that we are "working with the same raw material as exists in the animal world, but [we] can conceptualize and categorize it to serve social ends." [ 1 ]  These social ends include the socialization of children and the formation of basic economic, political and religious groups.


Kinship can refer both to the patterns of social relationships themselves, or it can refer to the study of the patterns of social relationships in one or more human cultures (i.e. kinship studies). Over its history,  anthropology  has developed a number of related concepts and terms in the study of kinship, such as  descent , descent group,  lineage ,  affinity/affine ,  consanguinity/cognate  and  fictive kinship . Further, even within these two broad usages of the term, there are different theoretical approaches.


Broadly, kinship patterns may be considered to include people related by both  descent  – i.e. social relations during development – and by  marriage . Human kinship relations through  marriage  are commonly called "affinity" in contrast to the relationships that arise in one's group of origin, which may be called one's descent group. In some cultures, kinship relationships may be considered to extend out to people an individual has economic or political relationships with, or other forms of social connections. Within a culture, some descent groups may be considered to lead back to  gods [ 2 ]  or animal ancestors ( totems ). This may be conceived of on a more or less literal basis.


Kinship can also refer to a principle by which individuals or groups of individuals are organized into  social groups , roles, categories and  genealogy  by means of  kinship terminologies .  Family  relations can be represented concretely (mother, brother, grandfather) or abstractly by degrees of relationship (kinship distance). A relationship may be relative (e.g. a father in relation to a child) or reflect an absolute (e.g. the difference between a mother and a childless woman). Degrees of relationship are not identical to  heirship  or legal succession. Many codes of  ethics  consider the bond of kinship as creating obligations between the related persons stronger than those between strangers, as in  Confucian   filial piety .


In a more general sense, kinship may refer to a similarity or  affinity  between entities on the basis of some or all of their characteristics that are under focus. This may be due to a shared  ontological  origin, a shared historical or cultural connection, or some other perceived shared features that connect the two entities. For example, a person studying the ontological roots of human languages ( etymology ) might ask whether there is kinship between the English word  seven  and the German word  sieben . It can be used in a more diffuse sense as in, for example, the news headline " Madonna  feels kinship with vilified  Wallis Simpson ", to imply a felt similarity or  empathy  between two or more entities.


In  biology , "kinship" typically refers to the degree of genetic relatedness or the  coefficient of relationship  between individual members of a species (e.g. as in  kin selection  theory). It may also be used in this specific sense when applied to human relationships, in which case its meaning is closer to  consanguinity  or  genealogy .


Family is a  group  of  people  affiliated by  consanguinity  (by recognized birth),  affinity  (by marriage), or co-residence/shared consumption (see  Nurture kinship ). In most societies, it is the principal institution for the socialization of children. As the basic unit for raising children, Anthropologists most generally classify family organization as  matrifocal  (a mother and her children); conjugal (a husband, his wife, and children; also called  nuclear family );  avuncular  (a brother, his sister, and her children); or  extended family  in which parents and children co-reside with other members of one parent's family.


However, producing children is not the only function of the family; in societies with a  sexual division of labor ,  marriage , and the resulting relationship between two people, it is necessary for the formation of an economically productive  household . [ 3 ] [ 4 ] [ 5 ]


Different societies classify kinship relations differently and therefore use different systems of  kinship terminology  – for example some languages distinguish between  affinal  and  consanguine  uncles, whereas others
have only one word to refer to both a father and his brothers. Kinship terminologies include the terms of address used in different languages or communities for different relatives and the terms of reference used to identify the relationship of these relatives to ego or to each other.


Kin terminologies can be either  descriptive  or  classificatory . When a descriptive terminology is used, a term refers to only one specific type of relationship, while a classificatory terminology groups many different types of relationships under one term. For example, the word  brother  in English-speaking societies indicates a son of one's same parent; thus, English-speaking societies use the word  brother  as a descriptive term referring to this relationship only. In many other classificatory kinship terminologies, in contrast, a person's male first cousin (whether mother's brother's son, mother's sister's son, father's brother's son, father's sister's son) may also be referred to as brothers.


The major patterns of kinship systems that are known which  Lewis Henry Morgan  identified through kinship terminology in his 1871 work  Systems of Consanguinity and Affinity of the Human Family  are:


There is a seventh type of system only identified as distinct later:


The six types (Crow, Eskimo, Hawaiian, Iroquois, Omaha, Sudanese) that are not fully classificatory (Dravidian, Australian) are those identified by Murdock (1949) prior to Lounsbury's (1964) rediscovery of the linguistic principles of classificatory kin terms.


While normal kin-terms discussed above denote a relationship between two entities (e.g. the word 'sister' denotes the relationship between the speaker or some other entity and another feminine entity who shares the parents of the former), trirelational kin-terms—also known as triangular, triadic, ternary, and shared kin-terms—denote a relationship between three distinct entities. These occur commonly in  Australian Aboriginal languages  with the context of  Australian Aboriginal kinship .


In  Bininj Kunwok , [ 6 ]  for example, the bi-relational kin-term  nakurrng  is differentiated from its tri-relational counterpart by the position of the possessive pronoun  ke . When  nakurrng  is anchored to the addressee with  ke  in the second position, it simply means 'brother' (which includes a broader set of relations than in English). When the  ke  is fronted, however, the term  nakurrng  now incorporates the male speaker as a propositus ( P  i.e. point of reference for a kin-relation) and encapsulates the entire relationship as follows:


Many Australian languages also have elaborate systems of referential terms for denoting groups of people based on their relationship to one another (not just their relationship to the speaker or an external propositus like 'grandparents'). For example, in  Kuuk Thaayorre ,  a maternal grandfather and his sister are referred to as  paanth ngan-ngethe  and addressed with the vocative  ngethin. [ 7 ]  In  Bardi , a father and his sister are  irrmoorrgooloo ; a man's wife and his children are  aalamalarr.


In  Murrinh-patha , nonsingular pronouns are differentiated not only by the gender makeup of the group, but also by the members' interrelation. If the members are in a sibling-like relation, a third pronoun (SIB) will be chosen distinct from the Masculine (MASC) and Feminine/Neuter (FEM). [ 8 ]


In many societies where kinship connections are important, there are rules, though they may be expressed or be taken for granted. There are four main headings that anthropologists use to categorize rules of descent. They are  bilateral ,  unilineal ,  ambilineal  and double descent. [ 9 ]


A descent group is a  social group  whose members talk about common ancestry. A  unilineal  society is one in which the descent of an individual is reckoned either from the mother's or the father's line of descent.  Matrilineal descent  is based on relationship to females of the family line. A child would not be recognized with their father's family in these societies, but would be seen as a member of their mother's family's line. [ 10 ]  Simply put, individuals belong to their mother's descent group. Matrilineal descent includes the mother's brother, who in some societies may pass along inheritance to the sister's children or succession to a sister's son. Conversely, with  patrilineal descent , individuals belong to their father's descent group. Children are recognized as members of their father's family, and descent is based on relationship to males of the family line. [ 10 ]  Societies with the  Iroquois kinship  system, are typically unilineal, while the Iroquois proper are specifically matrilineal.


In a society which reckons descent bilaterally (bilineal), descent is reckoned through both father and mother, without unilineal descent groups. Societies with the  Eskimo kinship  system, like the  Inuit ,  Yupik , and most Western societies, are typically bilateral. The egocentric kindred group is also typical of bilateral societies. Additionally, the Batek people of Malaysia recognize kinship ties through both parents' family lines, and kinship terms indicate that neither parent nor their families are of more or less importance than the other. [ 11 ]


Some societies reckon descent patrilineally for some purposes, and matrilineally for others. This arrangement is sometimes called double descent. For instance, certain property and titles may be inherited through the male line, and others through the female line.


Societies can also consider descent to be  ambilineal  (such as  Hawaiian kinship ) where offspring determine their lineage through the  matrilineal line  or the  patrilineal line .


A lineage is a  unilineal descent  group that can demonstrate their common descent from a known  apical ancestor . Unilineal lineages can be matrilineal or patrilineal, depending on whether they are traced through mothers or fathers, respectively. Whether matrilineal or patrilineal descent is considered most significant differs from culture to culture.


A  clan  is generally a descent group claiming common descent from an apical ancestor. Often, the details of parentage are not important elements of the clan tradition. Non-human apical ancestors are called  totems . Examples of clans are found in  Chechen ,  Chinese ,  Irish ,  Japanese ,  Polish ,  Scottish ,  Tlingit , and  Somali  societies.


A  phratry  is a descent group composed of three or more clans each of whose apical ancestors are descended from a further common ancestor.


If a society is divided into exactly two descent groups, each is called a  moiety , after the  French  word for  half . If the two halves are each obliged to marry out, and into the other, these are called matrimonial  moieties . Houseman and White (1998b, bibliography) have discovered numerous societies where kinship network analysis shows that two halves marry one another, similar to matrimonial moieties, except that the two halves—which they call matrimonial  sides [ 12 ] —are neither named nor descent groups, although the egocentric kinship terms may be consistent with the pattern of sidedness, whereas the sidedness is culturally evident but imperfect. [ 13 ]


The word  deme  refers to an endogamous local population that does not have unilineal descent. [ 14 ]  Thus, a deme is a local endogamous community without internal segmentation into clans.


In some societies kinship and political relations are organized around membership in corporately organized dwellings rather than around  descent groups  or  lineages , as in the " House of Windsor ". The concept of a house society was originally proposed by  Claude Lévi-Strauss  who called them " sociétés à maison ". [ 15 ] [ 16 ]  The concept has been applied to understand the organization of societies from  Mesoamerica  and the  Moluccas  to  North Africa  and medieval Europe. [ 17 ] [ 18 ]  Lévi-Strauss introduced the concept as an alternative to 'corporate kinship group' among the cognatic kinship groups of the Pacific region. The socially significant groupings within these societies have variable membership because kinship is reckoned bilaterally (through both father's and mother's kin) and comes together for only short periods. Property, genealogy and residence are not the basis for the group's existence. [ 19 ]


Marriage is a socially or ritually recognized union or legal contract between  spouses  that establishes rights and obligations between them, between them and their children, and between them and their in-laws. [ 20 ]  The definition of marriage varies according to different cultures, but it is principally an  institution  in which interpersonal relationships, usually  intimate  and sexual, are acknowledged. When defined broadly, marriage is considered a  cultural universal . A broad definition of marriage includes those that are  monogamous ,  polygamous ,  same-sex  and temporary.


The act of marriage usually creates  normative  or legal obligations between the individuals involved, and any offspring they may produce. Marriage may result, for example, in "a union between a man and a woman such that children born to the woman are the recognized legitimate offspring of both partners." [ 21 ]  Edmund Leach argued that no one definition of marriage applied to all cultures, but offered a list of ten rights frequently associated with marriage, including sexual monopoly and rights with respect to children (with specific rights differing across cultures). [ 22 ]


There is wide cross-cultural variation in the social rules governing the selection of a partner for marriage. In many societies, the choice of partner is limited to suitable persons from specific social groups. In some societies the rule is that a partner is selected from an individual's own social group –  endogamy , this is the case in many class and caste based societies. But in other societies a partner must be chosen from a different group than one's own –  exogamy , this is the case in many societies practicing  totemic  religion where society is divided into several exogamous totemic clans, such as most  Aboriginal Australian  societies. Marriages between parents and children, or between full siblings, with few exceptions, [ 23 ] [ 24 ] [ 25 ] [ 26 ] [ 27 ] [ 28 ] [ 29 ]  have been considered  incest  and forbidden. However,  marriages between more distant relatives  have been much more common, with one estimate being that 80% of all marriages in history have been between second cousins or closer. [ 30 ]


Systemic forms of preferential marriage may have wider social implications in terms of economic and political organization. In a wide array of lineage-based societies with a  classificatory kinship system , potential spouses are sought from a specific class of relatives as determined by a prescriptive marriage rule. Insofar as regular marriages following prescriptive rules occur, lineages are linked together in fixed relationships; these ties between lineages may form political alliances in kinship dominated societies. [ 31 ]  French  structural  anthropologist  Claude Lévi-Strauss  developed the  alliance theory  to account for the "elementary" kinship structures created by the limited number of prescriptive marriage rules possible. [ 32 ]


Claude Lévi-Strauss argued in  The Elementary Structures of Kinship  (1949), that the  incest taboo  necessitated the exchange of women between kinship groups. Levi-Strauss thus shifted the emphasis from descent groups to the stable  structures  or relations between groups that preferential and prescriptive marriage rules created. [ 33 ]


One of the foundational works in the anthropological study of kinship was  Morgan's   Systems of Consanguinity and Affinity of the Human Family  (1871). As is the case with other social sciences, Anthropology and kinship studies emerged at a time when the understanding of the Human species' comparative place in the world was somewhat different from today's. Evidence that life in stable social groups is not just a feature of humans, but also of many other  primates , was yet to emerge and  society  was considered to be a uniquely human affair. As a result, early kinship theorists saw an apparent need to explain not only the details of  how  human social groups are constructed, their patterns, meanings and obligations, but also  why  they are constructed at all. The  why  explanations thus typically presented the fact of life in social groups ( which appeared to be unique to humans ) as being largely a result of human ideas and values.


Morgan's explanation for why humans live in groups was largely based on the notion that all humans have an inherent  natural valuation  of genealogical ties (an unexamined assumption that would remain at the heart of kinship studies for another century, see below), and therefore also an inherent desire to construct social groups around these ties. Even so, Morgan found that members of a society who are  not  close genealogical relatives may nevertheless use what he called  kinship terms  (which he considered to be originally based on genealogical ties). This fact was already evident in his use of the term  affinity  within his concept of the  system of kinship . The most lasting of Morgan's contributions was his discovery of the difference between descriptive and  classificatory kinship  terms, which situated broad kinship classes on the basis of imputing abstract social patterns of relationships having little or no overall relation to genetic closeness but instead cognition about kinship, social distinctions as they affect linguistic usages in  kinship terminology , and strongly relate, if only by approximation, to patterns of marriage. [ 13 ]


Source: [ 34 ]


A more flexible view of kinship was formulated in British  social anthropology . Among the attempts to break out of universalizing assumptions and theories about kinship,  Radcliffe-Brown  (1922, The  Andaman Islands ; 1930, The social organization of Australian tribes) was the first to assert that kinship relations are best thought of as concrete networks of relationships among individuals. He then described these relationships, however, as typified by interlocking interpersonal roles.  Malinowski  (1922, Argonauts of the Western Pacific) described patterns of events with concrete individuals as participants stressing the relative stability of institutions and communities, but without insisting on abstract systems or models of kinship.  Gluckman  (1955, The judicial process among the Barotse of Northern Rhodesia) balanced the emphasis on stability of institutions against processes of change and conflict, inferred through detailed analysis of instances of social interaction to infer rules and assumptions.  John Barnes ,  Victor Turner , and others, affiliated with Gluckman's Manchester school of anthropology, described patterns of actual network relations in communities and fluid situations in urban or migratory context, as with the work of  J. Clyde Mitchell  (1965, Social Networks in Urban Situations). Yet, all these approaches clung to a view of stable  functionalism , with kinship as one of the central stable institutions. More recently, under the influence of "new kinship studies", there has been a shift of emphasis from the being to the doing of kinship. A new generation of anthropologist study the processes of doing kinship in new contexts such as in migrant communities [ 35 ]  and in queer families. [ 36 ]


The concept of "system of kinship" tended to dominate anthropological studies of kinship in the early 20th century. Kinship systems as defined in anthropological texts and ethnographies were seen as constituted by patterns of behavior and attitudes in relation to the differences in terminology, listed above, for referring to relationships as well as for addressing others. Many anthropologists went so far as to see, in these patterns of kinship, strong relations between  kinship categories  and patterns of marriage, including forms of marriage, restrictions on marriage, and cultural concepts of the boundaries of  incest . A great deal of inference was necessarily involved in such constructions as to "systems" of kinship, and attempts to construct systemic patterns and reconstruct kinship evolutionary histories on these bases were largely invalidated in later work. However, anthropologist Dwight Read later argued that the way in which kinship categories are defined by individual researchers are substantially inconsistent. [ 37 ]  This not only occurs when working within a systemic cultural model that can be elicited in fieldwork, but also when allowing considerable individual variability in details, such as when they are recorded through relative products. [ 38 ]


In trying to resolve the problems of dubious inferences about kinship "systems",  George P. Murdock  (1949, Social Structure) compiled kinship data to test a theory about universals in human kinship in the way that terminologies were influenced by the behavioral similarities or social differences among pairs of kin, proceeding on the view that the psychological ordering of kinship systems radiates out from ego and the  nuclear family  to different forms of  extended family .  Lévi-Strauss  (1949, Les Structures Elementaires), on the other hand, also looked for global patterns to kinship, but viewed the  "elementary" forms  of kinship as lying in the ways that families were connected by marriage in different fundamental forms resembling those of  modes of exchange : symmetric and direct, reciprocal delay, or  generalized exchange . [ 39 ]


Building on Lévi-Strauss's (1949) notions of kinship as caught up with the fluid languages of exchange,  Edmund Leach  (1961, Pul Eliya) argued that kinship was a flexible idiom that had something of the grammar of a language, both in the uses of terms for kin but also in the fluidities of language, meaning, and networks. His field studies criticized the ideas of structural-functional stability of kinship groups as corporations with charters that lasted long beyond the lifetimes of individuals, which had been the orthodoxy of  British Social Anthropology . This sparked debates over whether kinship could be resolved into specific organized sets of rules and components of meaning, or whether kinship meanings were more fluid, symbolic, and independent of grounding in supposedly determinate relations among individuals or groups, such as those of descent or prescriptions for marriage.


From the 1950s onwards, reports on kinship patterns in the New Guinea Highlands added some momentum to what had until then been only occasional fleeting suggestions that living together (co-residence) might underlie social bonding, and eventually contributed to the general shift away from a genealogical approach (see below section). For example, on the basis of his observations, Barnes suggested:


[C]learly, genealogical connexion of some sort is one criterion for membership of many social groups. But it may not be the only criterion; birth, or residence, or a parent's former residence, or utilization of garden land, or participation in exchange and feasting activities or in house-building or raiding, may be other relevant criteria for group membership."(Barnes 1962,6) [ 40 ]


Similarly, Langness' ethnography of the  Bena Bena  also emphasized the primacy of residence patterns in 'creating' kinship ties:


The sheer fact of residence in a Bena Bena group can and does determine kinship.   People do not necessarily reside where they do because they are kinsmen: rather they become kinsmen because they reside there."  (Langness 1964, 172 emphasis in original) [ 41 ]


In 1972  David M. Schneider  raised [ 42 ]  deep problems with the notion that human social bonds and 'kinship' was a natural category built upon genealogical ties and made a fuller argument in his 1984 book  A Critique of the Study of Kinship [ 43 ]  which had a major influence on the subsequent study of kinship.


Before the questions raised within anthropology about the study of 'kinship' by  David M. Schneider [ 43 ]  and others from the 1960s onwards, anthropology itself had paid very little attention to the notion that kinship bonds were anything other than connected to consanguineal (or genealogical) relatedness (or its local cultural conceptions). Schneider's 1968 study [ 44 ]  of the symbolic meanings surrounding ideas of kinship in American Culture found that Americans ascribe a special significance to 'blood ties' as well as related symbols like the naturalness of marriage and raising children within this culture. In later work (1972 and 1984) Schneider argued that unexamined genealogical notions of kinship had been embedded in anthropology since Morgan's early work [ 45 ]  because American anthropologists (and anthropologists in western Europe) had made the mistake of assuming these  particular cultural values  of 'blood is thicker than water', common in their own societies, were 'natural' and universal for all human cultures (i.e. a form of ethnocentrism). He concluded that, due to these unexamined assumptions, the whole enterprise of 'kinship' in anthropology may have been built on faulty foundations. His 1984 book  A Critique of The Study of Kinship  gave his fullest account of this critique.


Certainly for Morgan (1870:10) the actual bonds of blood relationship had a force and vitality of their own quite apart from any social overlay which they may also have acquired, and it is this biological relationship itself which accounts for what Radcliffe-Brown called "the source of social cohesion". (Schneider 1984, 49)


Schneider himself emphasised a distinction between the notion of a social relationship as intrinsically  given  and inalienable ( from birth ), and a social relationship as created, constituted and maintained by a process of interaction, or  doing  (Schneider 1984, 165). Schneider used the example of the citamangen / fak relationship in Yap society, that his own early research had previously glossed over as a  father / son  relationship, to illustrate the problem;


The crucial point is this: in the relationship between  citamangen  and  fak  the stress in the definition of the relationship is more on doing than on being. That is, it is more what the  citamangen  does for  fak  and what  fak  does for  citamangen  that makes or constitutes the relationship. This is demonstrated, first, in the ability to terminate absolutely the relationship where there is a failure in the doing, when the  fak  fails to do what he is supposed to do; and second, in the reversal of terms so that the old, dependent man becomes  fak , to the young man,  tam . The European and the anthropological notion of consanguinity, of blood relationship and descent, rest on precisely the opposite kind of value. It rests more on the state of being... on the biogenetic relationship which is represented by one or another variant of the symbol of 'blood' (consanguinity), or on 'birth', on qualities rather than on performance. We have tried to impose this definition of a kind of relation on all peoples, insisting that kinship consists in relations of consanguinity and that kinship as consanguinity is a universal condition.(Schneider 1984, 72)


Schneider preferred to focus on these often ignored processes of "performance, forms of doing, various codes for conduct, different roles" (p. 72) as the most important constituents of kinship. His critique quickly prompted a new generation of anthropologists to reconsider how they conceptualized, observed and described social relationships ('kinship') in the cultures they studied.


Schneider's critique is widely acknowledged [ 46 ] [ 47 ] [ 48 ]  to have marked a turning point in anthropology's study of social relationships and interactions. Some anthropologists moved forward with kinship studies by teasing apart biological and social aspects, prompted by Schneider's question;


The question of whether kinship is a privileged system and if so, why, remains without a satisfactory answer. If it is privileged because of its relationship to the functional prerequisites imposed by the nature of physical kinship, this remains to be spelled out in even the most elementary detail. (Schneider 1984, 163)


Schneider also dismissed the sociobiological account of biological influences, maintaining that these did not fit the ethnographic evidence (see more below).  Janet Carsten  employed her studies with the Malays [ 49 ]  to reassess kinship. She uses the idea of  relatedness  to move away from a pre-constructed analytic opposition between the biological and the social. Carsten argued that relatedness should be described in terms of indigenous statements and practices, some of which fall outside what anthropologists have conventionally understood as kinship;


Ideas about relatedness in Langkawi show how culturally specific is the separation of the 'social' from the 'biological' and the latter to sexual reproduction. In Langkawi relatedness is derived both from acts of procreation and from living and eating together. It makes little sense in indigenous terms to label some of these activities as social and others as biological. (Carsten 1995, 236)


Philip Thomas' work with the Temanambondro of  Madagascar  highlights that nurturing processes are considered to be the 'basis' for kinship ties in this culture, notwithstanding genealogical connections;


Yet just as fathers are not simply made by birth,  neither are mothers,  and although mothers are not made by  "custom" they,  like fathers,  can make themselves through another type of performatively constituted relation,  the giving of "nurture". Relations of ancestry are particularly important in contexts of ritual,  inheritance and the defining of marriageability and incest;  they are in effect the  "structuring structures" (Bourdieu 1977)  of social reproduction and intergenerational continuity.  Father, mother and children are, however,  also performatively related through the giving and receiving of "nurture" (fitezana). Like ancestry, relations of "nurture" do not always coincide with relations by birth; but unlike ancestry, "nurture" is a largely ungendered relation, constituted in contexts of everyday practical existence, in the intimate, familial and familiar world of the household, and in ongoing relations of work and consumption, of feeding and farming. (Thomas 1999, 37) [ 50 ]


Similar ethnographic accounts have emerged from a variety of cultures since Schneider's intervention. The concept of  nurture kinship  highlights the extent to which kinship relationships may be brought into being through the performance of various acts of nurture between individuals. Additionally the concept highlights ethnographic findings that, in a wide swath of human societies, people understand, conceptualize and symbolize their relationships predominantly in terms of giving, receiving and sharing nurture. These approaches were somewhat forerun by  Malinowski , in his  ethnographic  study of  sexual behaviour  on the  Trobriand Islands  which noted that the Trobrianders did not believe pregnancy to be the result of  sexual intercourse  between the man and the woman, and they denied that there was any physiological relationship between father and child. [ 51 ]  Nevertheless, while paternity was unknown in the "full biological sense", for a woman to have a child without having a husband was considered socially undesirable. Fatherhood was therefore recognised as a social and nurturing role; the woman's husband is the "man whose role and duty it is to take the child in his arms and to help her in nursing and bringing it up"; [ 52 ]  "Thus, though the natives are ignorant of any physiological need for a male in the constitution of the family, they regard him as indispensable socially". [ 53 ]


Like Schneider, other anthropologists of kinship have largely rejected sociobiological accounts of human social patterns as being both reductionistic and also empirically incompatible with ethnographic data on human kinship. Notably,  Marshall Sahlins  strongly critiqued the sociobiological approach through reviews of ethnographies in his 1976  The Use and Abuse of Biology [ 54 ]  noting that for humans "the categories of 'near' and 'distant' [kin] vary independently of consanguinal distance and that these categories organize actual social practice" (p. 112).


Independently from anthropology, biologists studying organisms' social behaviours and relationships have been interested to understand under what conditions significant social behaviors can evolve to become a typical feature of a species (see  inclusive fitness  theory). Because complex social relationships and cohesive social groups are common not only to humans, but also to most primates, biologists maintain that these biological theories of sociality should in principle be generally applicable. The more challenging question arises as to how such ideas can be applied to the human species whilst fully taking account of the extensive ethnographic evidence that has emerged from anthropological research on kinship patterns.


Early developments of biological  inclusive fitness  theory and the derivative field of  Sociobiology , encouraged some  sociobiologists  and  evolutionary psychologists  to approach human kinship with the assumption that  inclusive fitness  theory predicts that kinship relations in humans  are indeed  expected to depend on genetic relatedness, which they readily connected with the  genealogy  approach of early anthropologists such as Morgan (see above sections). However, this is the position that Schneider, Sahlins and other anthropologists explicitly reject.


In agreement with Schneider,  Holland  argued [ 55 ]  that an accurate account of biological theory and evidence supports the view that social bonds (and kinship) are indeed mediated by a shared social environment and processes of frequent interaction, care and nurture, rather than by genealogical relationships  per se  (even if genealogical relationships frequently correlate with such processes). In his 2012 book  Social bonding and nurture kinship  Holland argues that sociobiologists and later evolutionary psychologists misrepresent biological theory, mistakenly believing that  inclusive fitness  theory predicts that genetic relatedness  per se  is the condition that  mediates  social bonding and social cooperation in organisms. Holland points out that the biological theory (see  inclusive fitness ) only specifies that a statistical relationship between social behaviors and genealogical relatedness is a criterion for the  evolution  of social behaviors. The theory's originator,  W. D. Hamilton  considered that organisms' social behaviours were likely to be mediated by general conditions that typically  correlate  with genetic relatedness, but are not likely to be mediated by genetic relatedness  per se [ 56 ]  (see  Human inclusive fitness  and  Kin recognition ). Holland reviews fieldwork from social mammals and primates to show that social bonding and cooperation in these species is indeed mediated through processes of shared living context, familiarity and  attachments , not by genetic relatedness  per se . Holland thus argues that both the biological  theory  and the biological  evidence  is nondeterministic and nonreductive, and that biology as a theoretical and empirical endeavor (as opposed to 'biology' as a cultural-symbolic nexus as outlined in Schneider's 1968 book) actually supports the  nurture kinship  perspective of cultural anthropologists working post-Schneider (see above sections). Holland argues that, whilst there is nonreductive compatibility around human kinship between anthropology, biology and psychology, for a full account of kinship in any  particular  human culture, ethnographic methods, including accounts of the people themselves, the analysis of historical contingencies, symbolic systems, economic and other cultural influences, remain centrally important.


Holland's position is widely supported by both cultural anthropologists and biologists as an approach which, according to Robin Fox,  "gets to the heart of the matter concerning the contentious relationship between kinship categories, genetic relatedness and the prediction of behavior" . [ 57 ]


The other approach, that of Evolutionary psychology, continues to take the view that genetic relatedness (or  genealogy ) is key to understanding human kinship patterns. In contrast to Sahlin's position (above), Daly and Wilson argue that "the categories of 'near' and 'distant' do not 'vary independently of consanguinal distance', not in any society on earth." (Daly et al. 1997, [ 58 ]  p282). A current view is that humans have an inborn but culturally affected system for detecting certain forms of genetic relatedness. One important factor for  sibling  detection, especially relevant for older siblings, is that if an infant and one's mother are seen to care for the infant, then the infant and oneself are assumed to be related. Another factor, especially important for younger siblings who cannot use the first method, is that persons who grew up together see one another as related. Yet another may be genetic detection based on the  major histocompatibility complex  (See  Major Histocompatibility Complex and Sexual Selection ). This kinship detection system in turn affects other genetic predispositions such as the  incest taboo  and a tendency for  altruism  towards relatives. [ 59 ]


One issue within this approach is why many societies organize according to descent (see below) and not exclusively according to kinship. An explanation is that kinship does not form clear boundaries and is centered differently for each individual. In contrast, descent groups usually do form clear boundaries and provide an easy way to create cooperative groups of various sizes. [ 60 ]


According to an evolutionary psychology hypothesis that assumes that descent systems are optimized to assure high genetic probability of relatedness between lineage members, males should prefer a patrilineal system if paternal certainty is high; males should prefer a matrilineal system if paternal certainty is low. Some research supports this association with one study finding no patrilineal society with low paternity confidence and no matrilineal society with high paternal certainty. Another association is that  pastoral  societies are relatively more often patrilineal compared to  horticultural  societies. This may be because wealth in pastoral societies in the form of mobile cattle can easily be used to pay  bride price  which favor concentrating resources on sons so they can marry. [ 60 ]


The evolutionary psychology account of biology continues to be rejected by most cultural anthropologists.


As social and biological concepts of parenthood are not necessarily coterminous, the terms "pater" and "genitor" have been used in anthropology to distinguish between the man who is socially recognised as father (pater) and the man who is believed to be the physiological parent (genitor); similarly the terms "mater" and "genitrix" have been used to distinguish between the woman socially recognised as mother (mater) and the woman believed to be the physiological parent (genitrix). [ 61 ]  Such a distinction is useful when the individual who is considered the legal parent of the child is not the individual who is believed to be the child's biological parent. For example, in his ethnography of the  Nuer ,  Evans-Pritchard  notes that if a  widow , following the death of her husband, chooses to live with a lover outside of her deceased husband's kin group, that lover is only considered genitor of any subsequent children the widow has, and her deceased husband continues to be considered the pater. As a result, the lover has no legal control over the children, who may be taken away from him by the kin of the pater when they choose. [ 62 ]  The terms "pater" and "genitor" have also been used to help describe the relationship between children and their parents in the context of divorce in Britain. Following the divorce and remarriage of their parents, children find themselves using the term "mother" or "father" in relation to more than one individual, and the pater or mater who is legally responsible for the child's care, and whose  family name  the child uses, may not be the genitor or genitrix of the child, with whom a separate parent-child relationship may be maintained through arrangements such as  visitation rights  or  joint custody . [ 63 ]


It is important to note that the terms "genitor" or "genetrix" do not necessarily imply actual biological relationships based on  consanguinity , but rather refer to the socially held belief that the individual is physically related to the child, derived from culturally held ideas about how biology works. So, for example, the  Ifugao  may believe that an illegitimate child might have more than one physical father, and so nominate more than one genitor. [ 64 ]  J.A. Barnes therefore argued that it was necessary to make a further distinction between genitor and genitrix (the supposed biological mother and father of the child), and the actual  genetic  father and mother of the child making them share their genes or genetics .


The study of kinship may be abstracted to  binary relations  between people. For example, if  x  is the  parent  of  y , the relation may be symbolized as  xPy . The  converse relation , that  y  is the child of  x , is written  yP T x . Suppose that  z  is another child of  x :  zP T x . Then  y  is a  sibling  of  z  as they share the parent  x :  zP T xPy  →  zP T Py . Here the relation of siblings is expressed as the composition  P T P  of the parent relation with its inverse.


The relation of  grandparent  is the composition of the parent relation with itself:  G  =  PP . An  uncle  or  aunt  is the sibling of a parent,  (P T P)P , which can also be interpreted as the child of a grandparent,  P T (PP) . Suppose  x  is the grandparent of  y :  xGy . Then  y  and  z  are  cousins  if  yG T xGz .


The symbols applied here to express kinship are used more generally in  algebraic logic  to develop a calculus of relations with sets other than human beings.


Abang Okpo Nyuserre Ini  as popular known in  Oron Nation  is the grandson of  Nyuserre Ini , he is also known as the Ancestral and putative father of the  Oron  Ukpabang people predominant in present day  Akwa Ibom State ,  Cross River State  of Nigeria and the Cameroon. [ 1 ]


According to Oron folklores Abang was the grandson of  Nyuserre Ini  an  Ancient Egyptian   pharaoh , the sixth ruler of the  Fifth Dynasty  during the  Old Kingdom  period. Nyuserre was the younger son of  Neferirkare Kakai  and queen  Khentkaus II , and the brother of the short-lived king  Neferefre  (meaning "least they forget" in Oron). He is credited with a reign of 24 to 35 years depending on the scholar, and likely lived in the second half of the 25th century BCE.
Abang left the Mediterranean region with his followers in the 24th century BCE at a tender age in other to establish a new Kingdom. [ 2 ]


Oron folklore tells of Abang Okpo as a powerful warrior and the Chief wrestler of the art-form known as `Mbok'. The wrestling known as (Mbok) has been part and parcel of the Oron people and the date of its origin is unknown. It is said that Abang and his followers made it popular in the Mediterranean.


Abang in his advent of establishing a kingdom was said to have wandered with his children and followers through he Sudanic belt possibly presently into present Uganda, Zaire  Congo Basin  as a result of the war of the Pygmies (a dwarfish people of Equatorial Africa) which had scattered most of the Africans – known to Oro people as


“ekung amamisim-isim asuan ofid oduobot".


then they settle within the region now known as Jigawa State in Nigeria which is written and pronounce as `Oronny` inline with Oros` phonemes migration,  as he was not comfortable among the Hausa, he made a major stop in the Cameroons Usahadit and Bakassi precisely called Isangele (Usakedet), That is why there is a prevalence of Oron names as Akan, Ekang, Abang, Etong, Osung, and Etang in the Cameroons today. [ 3 ]


At Usangale Abang begot Do, who begat Donni, who in turn beget Oron and Obolo and their children with others in Usahadit. This tradition emphasize the now and former accepted relationship between the  Oron people  and  Obolo people , Oro (called Adon by the Obolo) who is said to have led the people out of Cameroon, which have been celebrated between them in the past and present till the 1940s.


Abang, his followers and their descendants did not know that other people were already established on that land and due to dispute over farmland, and fishing space, The group later move on to their original homeland of  Oron Nation ,  Andoni people  and  Bakassi [ 4 ]  without Abang who died in Usahadit.


Adult adoption  is a form of  adoption  between two or more adults in order to transfer  inheritance  rights and/or  filiation .  Adult adoption may be done for various reasons including:  to establish  intestate inheritance rights ; [ 1 ]  to formalize a  step-parent/step-child  relationship or a  foster parent/foster child  relationship; or to restore the original legal relationship between adult adoptees and their biological families. [ 2 ]


In Japan, adult adoption  may be used in order to facilitate the continuance of a family business. [ 3 ]  This form of adoption is known as  mukoyōshi  ("son-in-law adoption"). [ 4 ]


Depending on the laws of the jurisdiction, adult adoption may not be available as a legal option.  In the United Kingdom, only children may be adopted.  The  Adoption and Children Act (2002)  states, "An application for an adoption order may only be made if the person to be adopted has not attained the age of 18 years on the date of the application." [ 5 ]


In places where adult adoptions exist, it may or may not transfer  filiation  in addition to inheritance rights.  For example, in Colorado, one can adopt an adult of age 21 or older for inheritance purposes, but filiation will remain unaffected. [ 6 ]  However, adoption of a person between the ages of 18 and 20 (inclusive) transfers both inheritance rights and filiation. [ 7 ]   In most other American states, both filiation and inheritance rights are transferred. [ citation needed ]  In countries where same-sex couples have not received the same legal protections as heterosexual couples, adult adoption of a partner has been used to ensure the property transfer to the surviving partner upon death. [ 8 ] [ 9 ] [ 10 ]


During the 1980s and 1990s, in absence of recognition of same-sex marriage, adult adoption was a way used by some persons having same-sex preference to let their partner inherit their estates. [ 11 ]  The process however involved the convoluted process of first getting rid of the formal parent child relationship of the adoptee from his/her biological parents and then applying for an adult adoption where his/her partner would be the adopter. In the 2010 book  Equality for Same-Sex Couples: The Legal Recognition of Gay Partnerships in Europe and the United States,  author Yuval Merin called adult adoption among same-sex couples "problematic" and noted that it had not gained popularity as a means to "circumvent the impossibility of same-sex marriage" at that time in the U.S. [ 12 ]


This  law -related article is a  stub . You can help Wikipedia by  expanding it .


In law and in  cultural anthropology ,  affinity  is the  kinship  relationship created or that exists between two people as a result of someone's  marriage . It is the relationship each party in the marriage has to the family of the other party in the marriage. It does not cover the  marital relationship  itself. Laws, traditions and customs relating to affinity vary considerably, sometimes ceasing with the death of one of the marriage partners through whom affinity is traced, and sometimes with the divorce of the marriage partners. In addition to kinship by marriage, "affinity" can sometimes also include kinship by  adoption  or a  step relationship .


Unlike blood relationships ( consanguinity ), which may have genetic consequences, affinity is essentially a social or moral construct, at times backed by legal consequences.


In law, affinity may be relevant in relation to prohibitions on  incestuous sexual relations  and in relation to whether particular couples are  prohibited from marrying . Which relationships are prohibited vary from jurisdiction to jurisdiction, and have varied over time. In some countries, especially in the past, the prohibited relationships were based on religious laws. In some countries, the prohibition on sexual relations between persons in an affinity relationship may be expressed in terms of  degrees of relationship . The degree of affinity is considered the same as the consanguineal level a couple was joined, so that, for example, the degree of affinity of a husband to his sister-in-law is two, the same as the wife would be to her sister on the basis of consanguinity. The degree to the wife’s parent or child is one, and to an aunt or niece it is three, and first cousin it is four. Though adoption and step relationships are cases of affinity, they are normally treated as consanguinity.


In law, affinity relatives by marriage are known as  affines . [ 1 ]


More commonly, they are known as  in-laws  or  family-in-law , with affinity being usually signified by adding  "-in-law"  to a degree of kinship. This is standard for the closest degrees of kinship, such as  parent-in-law ,  child-in-law ,  sibling-in-law , etc., but is frequently omitted in the case of more extended relations. As  uncle  and  aunt  are frequently used to refer indifferently to unrelated friends of the family, the terms may be used without specifying whether the person is a cognate or affine. Similarly, the spouse of a cousin may not be called a relation at all or may be referenced as a "cousin  by marriage ". "By-marriage" can also be used with "uncle" or "aunt", e.g.  Princess Léa of Belgium  is an aunt by marriage of King  Philippe of Belgium .


In  South Africa , sexual relations are prohibited within the first degree of affinity, that is, where one person is the direct ancestor or descendant of the spouse of the other person. [ 2 ]


Brazilian law, by the Article 1521 of the Civil Code, also extends the invalidity of marriage between parents and children to grandparents and grandchildren or any other sort of ascendant-descendant relationship (both consanguineous and adoptive), parents-in-law and children-in-law even after the divorce of the earlier couple, as well as to stepparents and stepchildren, and former spouses to an adoptive parent who did this unilaterally (regarded as an equivalent, in families formed by adoption, to stepparents and stepchildren); and extends the invalidity of marriage between siblings to biological cousin-siblings. [ 3 ] [ 4 ]


In  Hawaii , sexual penetration and marriage is prohibited within close degrees of affinity and is punishable by up to 5 years. [ 5 ]


In  Michigan , sexual contact between persons related "by blood or affinity to the third degree," and who are not lawfully married to each other, are chargeable as criminal sexual conduct in the 4th degree and punishable by a 2-year sentence or a fine of up to $500 or both. [ 6 ]


In  New Jersey , sexual contact is prohibited when the actor is "related to the victim by blood or affinity to the 3rd degree" and the victim is at least 16 but less than 18 years old. [ 7 ]


Al-Majdi fi Ansab al-Talibiyyin  ( Arabic :  ألمَجدی فی أنسابِ الطّالبیّین ,  lit.   ' Attributed to Majdi in the Lineages of the  Talibis  Peoples ' ) is an  Arabic  book written by  Ali ibn Muhammad Alawi Umari  known as  Ibn Sufi  on the subject of genealogy dating back to the fifth century  AH —11th century  AD/CE . In this work, the author discusses the genealogy of the descendants of the  Alawis  and the  Talebis , especially the genealogy of the first  Shiite   Imam ,  Ali  and his descendants. [ 3 ] [ 2 ] [ 4 ] [ 5 ] [ 6 ] [ 7 ] [ 8 ]  Almost a thousand years have passed since the life of this handwritten manuscript book. [ 9 ]


" Ali ibn Muhammad Alawi Umari " with the full name of " Najmuddin Abul-Hasan Ali ibn Abul-Ghanaim Alawi Umari " known as " Ibn Sufi " ( born  c.  1000   AD/CE — c.  390   AH  in  Basra , died  c.  1068   AD/CE — c.  460   AH  in  Mosul ) was a prominent  Shiite   genealogist . The famous  Arabic  historical genealogy book "Al-Majdi fi Ansabi al-Taalebiyin" ( in  Arabic :  ألمَجدی فی أنسابِ الطّالبیّین ,  lit.   ' Attributed to Majdi in the Lineages of the Talibis People ' ) was his most important work in his entire lifetime. [ 10 ] [ 11 ] [ 12 ] [ 13 ] [ 14 ] [ 15 ] [ 16 ]


Ibn Sufi was born and raised in  Basra , and is known as " Umari " and also " Alawi " due to his ancestry to his grandfather, " Umar al-Atraf ", the son of the first  Shia   Imam , " Ali ", known as " Ibn Taghlibiyah ". [ 17 ] [ 18 ]  Ibn Sufi's father, " Abu al-Ghana'im Muhammad ", known as " Ibn Mahlabiyah ", [ 19 ]  was considered as an authority on the  genealogy  science. [ 20 ]  In fact, genealogy had a long history in Ibn Sufi's family, and even his sixth grandfather, " Muhammad Sufi ", to whom Ibn Sufi is attributed and who was killed by order of  Harun al-Rashid  ( the fifth  Abbasid caliph  of the  Abbasid Empire ), [ 21 ]  was also a genealogist. [ 22 ]  It seems that Ibn Sufi spent most, if not all, of his time in  Baghdad  between 1016  AD/CE  to 1029  AD/CE  ( 407  AH  to 420  AH ). [ 23 ]  Ibn Sufi migrated from  Basra  to  Mosul  in 1032  AD/CE  ( 423  AH ), where he married and settled down. [ 24 ]  Ibn Sufi, [ 25 ]  in his account of the lineage of  Zayd ibn Ali , referred to  Twelver  school of thought as his own sect. According to  Ibn al-Tiqtaqa  ( a prominent historian ) in his book " Al-Asili ", Ibn Sufi died in  Mosul . [ 26 ]


As Ibn Sufi himself says, from childhood he studied various sciences, especially genealogy, and benefited from the presence of great masters. [ 27 ]   Ibn Tawus  ( a  Shiite  jurist, theologian, historian and astrologer ) considered Ibn Sufi as the foremost genealogist of his time, [ 28 ]  and according to  Ibn Inabah  ( a  Shiite   historian  and  genealogist ), [ 29 ]  Ibn Sufi's statement in the field of genealogy was a proof. Ibn Sufi traveled to many lands and cities to gain experience and knowledge in sciences specially in genealogy, such as  Ramla ,  Nusaybin ,  Levant , Mayafarfin,  Egypt ,  Oman ,  Kufa , and  Ukbara . [ 24 ]  Ibn Sufi has also been introduced by some historians as a writer, poet, and jurist. [ 30 ] [ 31 ]


The book "Al-Majdi fi Ansab al-Talibiyyin" includes the genealogy of the Islamic Prophet  Muhammad  and his family, especially the  twelve Shiite Imams . The subject of this book is the genealogy of  Sadat . Authentic  Shia   hadiths  have been used to prove the ratios mentioned in the book. [ 5 ]


The book "Al-Majdi fi Ansab al-Talibiyyin" was an important work on the subject of the Islamic genealogy dates back to the fifth century  AH —11th century  AD/CE , in which the author discusses the genealogies of the descendants of the  Alawites  and  Talebites , especially the genealogy of the first  Shia   Imam ,  Ali , and his descendants. [ 2 ]


The author first briefly discusses the lineage of the Islamic prophet  Muhammad  and then discusses the lineage of  Abu Talib ibn Abd al-Muttalib 's family. The three main parts of the book include the genealogy of the three sons of Abu Talib ibn Abd al-Muttalib, namely  Ali ,  Jafar , and  Aqil , and the description of the genealogy of the family of Ali, the first  Shiite   Imam , occupies a larger part. [ 2 ]


At the beginning of the description of  Ali 's lineage, the author also mentions his daughters and then introduces the lineage of Ali's first son and the second Imam of the Shiites,  Hassan ibn Ali , then introduces the lineage of Ali's second son and the third Imam of the Shiites,  Hussein ibn Ali , then introduces the lineage of Ali's third son  Muhammad ibn al-Hanafiyya , then introduces the lineage of Ali's another son  Abbas ibn Ali (Abu al-Fadl) , and then introduces the lineage of Ali's another son  Umar al-Atraf , who is the grandfather of the author of the book. Also, in the genealogy section of the descendants of Ali's second son, Hussein ibn Ali, the genealogies of the descendants of other Shiite Imams are briefly mentioned. [ 2 ]  In describing the lineage of each Shiite Imam, the author also provides a brief description of him, with a little more explanation about the  twelfth Shiite Imam ,  Muhammad al-Mahdi . [ 32 ] [ 3 ]


This book contains the genealogy of the  Alawites  and  Talebites  who migrated to lands outside the  Hijaz  and  Iraq , some of whom gained fame and status. [ 32 ]


The book begins with brief information about the genealogy of the Messenger of God, Islamic Prophet  Muhammad . At the beginning of the book, it is mentioned that the Islamic Prophet Muhammad, was born in the year known as the  Year of the Elephant  ( approximately equating to 570  CE ) in  Mecca  in  pre-Islamic Arabian , and his father,  Abdullah ibn Abd al-Muttalib , died before his birth, and he lost his mother at the age of six, and at the age of twenty, he participated in the Battle of  Fijar , and at the age of twenty-five, he  married   Khadija bint Khuwaylid , and at the age of sixty-three, he died of poisoning, and his tomb is in  Medina . [ 33 ]


The last section of the book is about the genealogy of the descendants of  Aqil ibn Abi Talib  ( an elder brother of  Ali ). This section mentions that Aqil ibn Abi Talib's  nickname  is " Abu Yazid " and that he had 18 sons. The final article in the book is about the genealogy of  Aqil ibn Abi Talib 's grandson, " Ja'far ibn Abdullah ibn Aqil ", who died in  Harran  in 946  CE —334  AH , and the final matter in the book is about his children who lived in  Aleppo ,  Beirut , and  Egypt . [ 34 ]


The book "Al-Majdi fi Ansab al-Talibiyyin" enjoyed considerable fame and prestige during the lifetime of its author and was popular in the East and West of the  Islamic world . [ 2 ]  This work is a classic and educational text in Islamic  genealogy , and Islamic genealogists consider it obligatory for elders to read it. [ 2 ]  In many Islamic genealogy books dating back to the fifth and sixth century  AH —11th and 12th century  AD/CE , the book "Al-Majdi fi Ansab al-Talibiyyin" is cited and quoted. This shows that the author of the book,  Ibn Sufi , was trusted by other genealogists of the time. [ 35 ]


The book "Al-Majdi fi Ansab al-Talibiyyin" is Ibn Sufi's most important book, written in the study of the lineage of the family of the prophet of  Islam   Muhammad , and the  Shiite   Imams . Ibn Sufi traveled to  Egypt  in 1051  AD/CE  ( 443  AH ), where he presented some of his works to " Majd al-Dawlah Abul-Hassan Ahmad " ( president of the House of Wisdom of the time ), during the  Fatimid Empire . [ 36 ]  " Abu Talib Muhammad ", the son of " Majd al-Dawlah Abul-Hassan Ahmad ", asked Ibn Sufi to write a brief book on genealogy. [ 37 ] [ 38 ]  Ibn Sufi also attributed the book to him in recognition of the kindness of " Majd al-Dawlah " and called it " Al-Majdi " in the first phrase of the book name which means " Attributed to Majdi " or " Dedicated to Majdi ". So, the book name  «ألمَجدی فی أنسابِ الطّالبیّین»  literally means " Dedicated to Majdi in the Lineages of the Talibis Peoples ". " Talibis Peoples " was a family tree in an  Arab  clan within the  Quraysh  tribe to which the Islamic prophet  Muhammad Ibn Abdullah  belonged. In fact, " Talibis Peoples " refers to  Abi Talib 's lineages and descendants. [ 38 ]


This book is known among Islamic genealogists as the abbreviated name of " Al-Majdi ". [ 39 ] [ 40 ]


In old Arabic manuscripts, after each matter, it was stated who and from what source the matter was quoted or narrated. This action was called "Quoting" or " Narrating " ( in  Arabic :  نَقل، رِوایَت ). [ 41 ]  " Narrating " also means word-of-mouth transmission. In ancient Arab times, the credibility of a manuscript depended on the quotes and narrations it used. If the narrator was known in society as a truthful and trustworthy person, then his statement would be considered as a valid proof. Therefore, the manuscripts that referred to reliable people and materials enjoyed a special reputation. [ 42 ] [ 43 ]


The book "Al-Majdi fi Ansab al-Talibiyyin" has many citations from reliable and trustworthy persons and matters in the field of genealogy. So, the book "Al-Majdi fi Ansab al-Talibiyyin" was famous in Islamic world among genealogists because of its reliable narrations and it's trustworthy author.  Ibn Sufi , the author of the book "Al-Majdi fi Ansab al-Talibiyyin", used the narrations he gave through his father, " Ibn Mahlabiyah ", and through " Ubaydoli " ( a reliable prominent genealogist ). In the book "Al-Majdi fi Ansab al-Talibiyyin", the author has narrated from the books, manuscripts, and commentaries belonging to the following individuals too: [ 44 ] [ 45 ]


The book "Al-Majdi fi Ansab al-Talibiyyin" was originally a manuscripts on the ancient handwriting paper. In fact, there have been several manuscripts of it. Some of the book's manuscripts have become defective and worn out over time, or have been burned in the fanatic conflicts. The surviving manuscripts which remains in the world include: [ 46 ]


In 1989  AD/CE  ( 1409  AH ), [ 48 ]  all the available original  Arabic  manuscripts of the book "Al-Majdi fi Ansab al-Talibiyyin" were collected and revived in the city of  Qom  ( the headquarters city of the Islamic scholars in  Iran ), and a modern-style academic version was republished with an introduction, commentaries, footnotes, and an afterword which is written by various experts. In this version, the main genealogy matters comes in  Arabic language  same as the original manuscripts sources, but it is a multi-language version which has many parts such as introduction, [ 49 ]  commentaries [ 9 ]  and afterword [ 50 ]  which comes in  Persian language . [ 51 ] [ 52 ] [ 53 ]


In the famous version of this book which is available in the Iranian book markets, the introduction was written by  Mahmoud Mar'ashi Najafi  ( an  Iranian   librarian ,  Bibliographer  and  manuscript expert ), in which he describes the biography of the author,  Ibn Sufi . [ 54 ]  The researches and guiding commentaries was done by  Ahmad Mahdavi Damghani  ( an Iranian scholar and university professor ), and most of the useful footnotes were mentioned by him. There is also a detailed introduction at the beginning of the book and comments and explanations at the end of the book, written by Ahmad Mahdavi Damghani too. The researcher in the field of ancient texts and the person who had an effective role in the revival of  Shiite  works " Abdulaziz Mohaqqiq Tabatabaei ", [ 55 ]  wrote an separate book in the commentaries of the book "Al-Majdi fi Ansab al-Talibiyyin" too. [ 53 ]


Ambilineality  is a form of kinship affiliation of  cognatic descent  that relies on self-defined affiliation within a given social system, meaning individuals have the choice to be affiliated with their mother's or father's group. Common features of societies that practice ambilineality are a shared set of land, communal responsibilities, and collective ownership of some segments of wealth and debt in their societies. [ 1 ]  This system of descent is distinct from more common genealogical structures in that rather than determining affiliation and descent using the standard determinants of biological and  genealogical  relation, it instead relies heavily on voluntary affiliation with one's group, oftentimes being determined by factors including residence.


Societies practicing ambilineal descent are especially common in  Southeast Asia [ 2 ]  and the  Pacific Islands .  Polynesian cultures  and  Micronesian cultures  are often ambilineal, including, for example,  Samoans ,  Māori , [ 3 ]   Hawaiians  and people of the  Gilbert Islands . [ 4 ]  The  indigenous peoples  of  Northwestern North America  are also followers of ambilineality; and it is also found among the Southern  Yoruba people  residing in  West Africa . [ 5 ]


Ambilineality is a  cognatic descent system  in which individuals may be affiliated either to their father's or mother's group. This type of descent results in descent groups which are non-unilineal in the sense that descent passes either through women or men, contrary to  unilineal descent , whether  patrilineal  or  matrilineal . Affiliation to a descent group will be determined either by choice or by residence. In the latter case, children will belong to the descent group with whom their parents are living.


Generally, an ambilineal descent group consists of known descendants who can trace their line of descent, through either the male or female line, to the individual who was given usage rights over the land. [ 6 ]


The grantee's descendants have absolute usage rights to a portion of land. If they are residents, they are to be appointed to leadership and administration positions relating to the governance of the land. Those living descendants of the chosen ancestor who follow these claims to land comprise an ambilineal descent group with corporate interests in the land granted to the ancestor. [ 7 ]


Similarly, inheritance is acquired through mother and father and property is transmitted through both sons and daughters, as all genders have the right to inheritance. [ 8 ]


As a  kinship system , ambilineality uses genealogy to trace descent either through the mother or the father. There is no set order in an ambilineal system to which the last name is chosen, and individuals may use both parents as links to a kin. [ 9 ]  In several cultures, such as the Tiwa, the choice of whether to associate with the male or female family is a personal decision. [ 10 ]


The choice of which familial line to trace descent may be influenced by culture. Societies may have a law or cultural customs determining whether to trace descent through the mother or father for a child's surname. This choice and tradition influences practices of the culture regarding which kin to associate with. Emphasis on descent through the female line came about because of people's interest in whitening their lineage since Brazilian women frequently married white European immigrants. Brazil did have an ambilineal system, but there was an underlying matrilineal emphasis. This was particularly common in the first hundred years of European colonization, particularly in Brazil. It was due to the Iberian concept of “purity of blood” (Spanish:  limpieza de sangre ) and their dislike of “infected” races such as Jews or Moors. [ 11 ]


In an ambilineal descent system the members can choose and change their affiliation or clan. This means that membership in an ambilineal group is associated with more freedom and is less binding and restricting than in unilineal descent groups. [ 12 ]  The flexibility of the descent group enables people to exercise a greater choice in their behavior towards kinsmen, especially distant kins. Furthermore, a person can choose whether or not they will honor their group responsibilities.


The ambilineal system also gives way to a more variable group membership and a more flexible group structure. Oftentimes people use the ability of choice to realign themselves with the more powerful or higher status option. For example, in the Togan people of the Northern Gilbert Islands it is common for a couple, with differing social status, to join the descent group with the higher status. [ 13 ]


The naming system in an ambilineal descent system allows for either using the mother or father's last name for the children or both, which is common in Latin America. Many societies have laws or strong cultural norms which dictate a child's surname. [ 14 ]  For example, in the U.S., it is the cultural custom for a child to have the father's surname, but in cases where the parents are not married, it is common for the child to take the surname of the mother. In the U.S., due to divorces and subsequent marriages, the surnames of children can also change. [ 15 ]


There is an ambilineal naming system in Spain and many Latin American countries, but with an implicit  patrilineality . Children have both their mother and their father's surnames, but grandchildren use their father's and mother's paternal surnames. In Brazil, the choice of surnames also has ambilineal tendencies. It depends on the personal desires of the parents or the person themselves, and modifying them was common in the first hundred years of colonization. However, it was the cultural tendency to use both the mother and the father's surnames following the general Spanish practice. [ 16 ]


In the Tiwa, it is a “personal choice” whether to live in the mother or father's home, indicating which “clan” they will join. Based on this choice, the children inherit the mother or father's surname when born into the respective clans. These choices reflect the understanding of belonging and identity. [ 17 ]


There have been disagreements on the topic of kinship terminology in ambilineal descent systems. While ambilineal  kinship terminology  is oftentimes described as either generational or using cross-generational relative age criterion, there is some push back on these ideas. [ 18 ]


Anthropologists have found that in ambilineal systems (such as those in Samoa) membership is often based on kinship criteria, but that one's role or label within the ambilineal group can be based on non-kinship criteria. This means that to determine if an individual is kin or not, genealogical criteria are often used, but once the individual is determined to be kin other (non-kinship) criteria will be used to designate a specific kin term. These kin distinctions within a group do not have any significance on the individual station as kinsmen. Because ambilineal sometimes do not have role allocation based on the “differentiation of kin-types” and kinship terminologies are based on such non-kin criteria some scholars have argued that in these groups kinships terms should not be used as terms of address. [ 19 ]


In Brazil, ambilineality is seen in choosing the surname of children, where it is common that a child takes both parents' surnames. During the first hundred years of colonization, it was common for families to trace lineage through matrilineal descent because of their interest in whitening their lineage. The Portuguese were concerned about the purity of blood, (see:  limpieza de sangre ) because of Jewish persecution and brought these ideas to Brazil. The European immigrants were primarily males until the 1800s; therefore, "mixed-blood" daughters could whiten their lineage by marrying and having children with white European immigrants. Over time, the generations became whiter and could, therefore, amass more power in Brazilian society. The Portuguese husbands provided more whiteness for the offspring, but the children would typically adopt the maternal surname if the wife's family were wealthier and more established. This is particularly true when the wife came from one of the more prominent families. Taking the mother's name identified the child as part of the family and gave access to the same power of the family. [ 20 ]


The Christian Amhara trace their descent ambilineally. They are considered as kin relatives from both the mother and father's side. Any Amhara is thus the descendant of a set of lineages which multiply rapidly back through the generations. The Amhara confer rights of inheritance on both sexes, recognize inheritance though both father and mother, and transmit goods through both sons and daughters. Whereas men and women have equal rights in theory, in practice, this does not always hold. [ 21 ]


Ambilineal descent also occurs amongst the Tegrefifin speakers who border the Amhara to the north although they have a clear bias in favor of the men. Nevertheless, their rules of inheritance and descent mean that Christian Ethiopians lack the patrilineal, narrow descent groups of western Christianity, and have a set of rules for transmitting property which tends towards radical fragmentation. [ 22 ]


Amongst the Christian Abyssinians, marriage happens outside the first seven degrees of consanguinity and work hard to live up to this rule. The laity seldom marry in church, instead marrying by secular contract under customary law. Polygyny was common amongst the Abbysnian nobility, characterized by rough equality. They lacked a strong sense of legitimacy or bastardy for children. Moreover, amongst Ethiopians, women had the right to initiate divorce and to take a share of the property from their marriage upon divorce. [ 23 ]


Abyssinian families are distinguished from other traditional Christian families by their prevalence of divorce and a pronounced ambilineality. However, they also have a strong culture of monogamy amongst Christian priests and their lay counterparts. [ 24 ]


In the  Tiwa (Lalung)  people who live at the Assam-Meghalaya border area in India, ambilineal descent is evident through their marriage and residence practices. At marriage each couple has the choice to join the wife or husband's clan. There are no set rules as to which house a couple occupies after marriage but, among the Tiwa people, gobhia (husband joining the wife's house) is more common than poari (wife joining husband's house). Any children born to the couple belong to the group chosen at the time of marriage. This means that an individual inherits the mother's name if born into her house or the father's name if born into his house. [ 25 ]


There is a spiritual dimension to ambilineal descent in Tiwa culture. Membership and affiliation to a descent group is expressed via surname (and domestic belonging/residence associated) as well as connection to deities. The Tiwas believe that there are numerous deities that inhabit the home. At birth a child inherits the house's descent group and the bonds that have been established between the god inhabiting the home. This affiliation with the deities serves as a principal criteria for lineage identification because the individual is associated with all of the houses within the descent group that are worshipping the same group deity. For example, two individuals who have the same surname could claim unrelatedness if they do not worship the same group deity. [ 26 ]


In Polynesia, numerous groups are found to have ambilineal descent systems. In the Northern Gilbert Islands ambilineal descent systems are evident in both  Butaritari  and  Makin . In both groups ambilineal descent is understood through land ownership, occupation, and inheritance. Membership in an ambilineal descent group, often called a ramage, includes those who can trace their descent (through either the female or male line) to the founder of the group, as well as individuals who can trace their descent to the founder and have inherited land rights to a part of the founder's estate. In this system an individual is not a member of every group they can genealogically trace kinship to. Rather, membership depends on land possession within the group. Upon marriage, couples have the choice in which group they want to join. [ 27 ]


Ambilineal systems are also found in  Samoa ,  Tonga  and with  Māori people  in New Zealand. Similarly to Butaritari and Makin, land ownership and inheritance is the basis for membership and affiliation in a descent group, but in these three systems membership is most often based on the male line. In this system, both the mother and father can be used for affiliation with a particular descent group, but emphasis is placed on the father. While it is most desirable for membership into the father's group female links are also used especially when aligning with the female line brings increased power, wealth, or social standing. [ 28 ]


An  ancestor , also known as a  forefather ,  fore-elder , or a  forebear , [ 1 ]  is a  parent  or ( recursively ) the parent of an  antecedent  (i.e., a  grandparent ,  great-grandparent , great-great-grandparent and so forth).  Ancestor  is "any person from whom one is descended. In law, the person from whom an  estate  has been  inherited ." [ 2 ]


Two individuals have a  genetic  relationship if one is the ancestor of the other or if they share a common ancestor. In  evolutionary  theory, species which share an evolutionary ancestor are said to be of  common descent . However, this concept of ancestry does not apply to some  bacteria  and other organisms capable of  horizontal gene transfer . Some research suggests that the average person has twice as many female ancestors as male ancestors. This might have been due to the past prevalence of  polygynous  relations and female  hypergamy . [ 3 ]


Assuming that all of an individual's ancestors are otherwise unrelated to each other, that individual has 2 n  ancestors in the  n th generation before them and a total of 2 g +1  − 2 ancestors in the  g  generations before them.  In practice, however, it is clear that most ancestors of humans (and any other species) are multiply related (see  pedigree collapse ). Consider  n  = 40: the human species is more than 40 generations old, yet the number 2 40 , approximately 10 12  or one trillion, dwarfs the  number of humans who have ever lived .


Some cultures confer reverence to ancestors, both living and dead; in contrast, some more youth-oriented cultural contexts display less veneration of elders. In other cultural contexts,  ancestor worship  or, more accurately,  ancestor veneration  is when people seek  providence [ further explanation needed ]  from their deceased ancestors. [ 4 ] [ 5 ]