Nipples can be sensitive to touch, and nipple stimulation can incite sexual arousal. [ 31 ]  Few women report experiencing orgasm from nipple stimulation. [ 32 ] [ 33 ]  Before Komisaruk et al.'s  functional magnetic resonance  (fMRI) research on nipple stimulation in 2011, reports of women achieving orgasm from nipple stimulation relied solely on  anecdotal evidence . [ 34 ]  Komisaruk's study was the first to map the female genitals onto the sensory portion of the brain; it indicates that sensation from the nipples travels to the same part of the brain as sensations from the vagina, clitoris and cervix, and that these reported orgasms are genital orgasms caused by nipple stimulation, and may be directly linked to the genital sensory  cortex  ("the genital area of the brain"). [ 34 ] [ 35 ] [ 36 ]


Women, on average, tend to be more attracted to men who have a relatively narrow waist, a V-shaped torso, and broad shoulders. Women also tend to be more attracted to men who are taller than they are, and display a high degree of  facial symmetry , as well as relatively masculine facial dimorphism. [ 37 ] [ 38 ]  Based on contemporary research and surveys, women, regardless of sexual orientation, are just as interested in a partner's physical attractiveness as men are. [ 39 ] [ 40 ] [ 41 ] [ 42 ] [ 43 ] [ 44 ] [ 45 ]


Historically, many cultures have viewed female sexuality as being subordinate to  male sexuality , and as something to be controlled through restrictions on female behavior. Traditional cultural practices, such as enforced  modesty  and  chastity , have tended to place restrictions principally on women, without imposing similar restrictions on men. [ 46 ]


According to  psychoanalytic  literature, the " Madonna–whore complex " is said to occur when a  male desires sexual encounters only with women whom he sees as degraded ("whores") while he cannot desire sexually a respectable woman ("the Madonna"). [ 47 ]  This was first described by  Sigmund Freud . [ 48 ]


The interpretation of female sexuality is significantly different according to  C.G. Jung 's psychological research. He explained the female libido as a precursor of cultural expression and personal creativity. He identified Freud's theories as the source of this significant misunderstanding, and theorized that the "rhythmic factor" is not merely a principle in the "nutritive phase" and later in sexuality, but that it is at the base of all emotional processes. [ 49 ]


Some controversial traditional cultural practices, such as  female genital mutilation  (FGM), have been described as attempts at nullifying women's sexuality altogether. FGM continues to be practised in some parts of Africa and the Middle East, as well as in some  immigrant  communities in Western countries, though it is widely outlawed. The procedure is typically carried out on young girls, before the age of 15. [ 50 ] [ 51 ]


Methods employed to control female sexuality and behavior include the threat of death, such as  honor killings . The reason for such a killing may include refusing to enter an arranged marriage, being in a relationship that is disapproved by their relatives, having sex outside marriage, becoming the victim of rape, or dressing in ways which are deemed inappropriate. [ 52 ] [ 53 ] [ 54 ]


Another historical device used to control female sexual behavior was the  chastity belt , which is a locking item of clothing designed to prevent sexual intercourse. The belts were worn by women to protect their chastity, which included preventing  masturbation  (such as by  fingering ) or sexual access by unauthorized males. [ 55 ] [ 56 ] [ 57 ]


Prior to the  European colonization of North America ,  Native American  attitudes regarding female sexuality were generally open-minded, particularly for younger, un-married women. However, when Europeans arrived, more rigid views were enforced. These rigid views were especially restrictive for women, predominantly in  Puritan  colonies. [ 58 ]


Following the European colonization of North America, there was the creation of the African American archetypes of the  Jezebel  and  mammy . The Jezebel was characterized as a woman who was lewd, tempting and seductive. [ 59 ]  Mammies, also called Aunt Jemima, were maternal figures who were portrayed as content within the institution of slavery – always with a smile on her face as the white family took up her life and her entire world. [ 60 ]  These stereotyping frameworks not only justified slavery but also justified the rape and abuse of African American women as being sexually driven, sexual beings in the case of the Jezebel, or a being where sex and sexuality are the last things on a woman's mind because her world is taken up by the lives of her white masters in the case of the mammy. [ 61 ] [ 62 ]


In the modern age, psychologists and physiologists explored female sexuality.  Sigmund Freud  propounded the theory of two kinds of female orgasms, "the vaginal kind, and the clitoral orgasm." However,  Masters and Johnson  (1966) and Helen O'Connell (2005) reject this distinction. [ 13 ] [ 63 ] [ 64 ] [ 65 ]


Ernst Gräfenberg  was famous for his studies of female genitalia and human female sexual physiology. He published, among other studies, the pioneering  The Role of Urethra in Female Orgasm  (1950), which describes female ejaculation, as well as an erogenous zone where the  urethra  is closest to the vaginal wall. In 1981, sexologists John D. Perry and  Beverly Whipple  named that area the Gräfenberg spot, or G-spot, in his honor. The medical community generally has not embraced the complete concept of the G-spot. [ 23 ] [ 24 ] [ 25 ]


Several studies establish that women are generally aroused by sexual stimuli of both sexes, while men are substantially aroused by stimuli of their preferred sex, and not of their non-preferred sex. This difference is consistent across different measures of arousal, such as genital response, pupil dilation, and viewing time. [ 66 ] [ 67 ]  Significant sexual arousal in response to both male and female sexual cues can be characterized as typical for females, while significant sexual arousal exclusively to one's preferred gender can be considered typical for males. [ 66 ]


In the 1970s and 1980s, long-held Western traditional views on female sexuality came to be challenged and reassessed as part of the  sexual revolution . The  feminist movement  and numerous feminist writers addressed female sexuality from a female perspective, rather than allowing female sexuality to be defined in terms of male sexuality. One of the first such popular non-fiction books was  Nancy Friday 's  My Secret Garden . Other writers, such as  Germaine Greer ,  Simone de Beauvoir  and  Camille Paglia , were particularly influential, although their views were not universally or placidly accepted. Toward the end of the 20th century the most significant European contributions to understanding female sexuality came from psychoanalytical  French feminism , with the work of  Luce Irigaray  and  Julia Kristeva .


Lesbianism  and female  bisexuality  also emerged as topics of interest within feminism. The concept of  political lesbianism , associated particularly with  second wave feminism  and  radical feminism , includes, but is not limited to,  lesbian separatism , notable proponents being  Sheila Jeffreys  and  Julie Bindel .


Feminist attitudes to female sexuality have varied in scope throughout the movement's history. Generally, modern feminists advocate for all women to have access to sexual healthcare and education, and agree on the importance of reproductive health freedoms, particularly regarding issues such as  birth control  and family planning. Bodily autonomy and consent are also concepts of high importance in modern feminist views of female sexuality.


Matters such as the  sex industry , sexual representation in the media, and issues regarding consent to sex under conditions of male dominance have been more controversial topics among feminists. These debates culminated in the late 1970s and the 1980s, in what came to be known as the  feminist sex wars , which pitted  anti-pornography feminism  against  sex-positive feminism . Parts of the feminist movement were deeply divided on these issues. [ 68 ] [ 69 ] [ 70 ] [ 71 ] [ 72 ]


Laws around the world affect the expression of female sexuality, and the circumstances under which an individual may not engage sexually with a woman or girl. Forced sexual encounters are usually prohibited, though some countries may sanction  rape in marriage .  Age of consent  laws, which differ between jurisdictions, set the minimum age at which a minor girl may engage in sex. In recent years, the age of consent has risen in some jurisdictions and has been lowered in others.


In some countries there are laws against  pornography  and  prostitution  (or certain aspects of those). Laws in some jurisdictions prohibit sex outside of marriage, such as  premarital sex  or  adultery , with critics arguing that, in practice, these laws are used to control women's and not men's behavior. [ 73 ] [ 74 ]  The  virginity  and  family honor  of women still play an important role in some legal systems: in some jurisdictions, the punishment for rape is more severe if the woman was a virgin at the time of the crime, and under some legal systems a man who rapes a woman can escape punishment if he marries her. [ 75 ]


With regard to the responsibility for safe sexual activity in heterosexual relationships, the commonly held definition of  safe sex  may be examined; it has been argued that there are three facets to the common perception of safe sex: emotional safety (trusting one's partner), psychological safety (feeling safe), and biomedical safety (the barrier of fluids which may cause pregnancy or transmit infection). The phrase "safe sex" is commonly known to refer to  biomedical  safety. [ 76 ]


Since the  sexual revolution , health officials have launched campaigns to bring awareness to the risks of unprotected sexual intercourse. While the dangers of unprotected sex include  unintended pregnancy ,  sexually transmitted infections  (STIs), with  HIV/AIDS  being the deadliest, the use of contraceptive devices (the most reliable being  condoms ) remain inconsistent. [ 77 ]


The  social construction  of  masculinity  and  femininity  play a lead role in understanding why women are commonly held responsible for the outcome of sexual encounters. Often, societies create different sexual norms and assumptions for women and men, with female and male sexuality often seen as being the opposite of one another: for example, females are commonly taught that they "should not want sexual activity or find it pleasurable, or have sexual relations outside of marriage," while males are commonly taught to "feel entitled to have sexual relations and pleasure and that their self-worth is demonstrated through their sexual prowess and notions of authority and power". [ 78 ] [ failed verification ]  Sexual interactions often take place in unequal structural circumstances in the context of imbalance of power between men and women. [ 78 ] [ 79 ]  Feminists, such as  Catharine Mackinnon , have stated that the inequality in which heterosexual intercourse takes place should not be ignored and should play a crucial role in policies; Mackinnon has argued: "The assumption is that women can be unequal to men economically, socially, culturally, politically, and in religion, but the moment they have sexual interactions, they are free and equal. That's the assumption – and I think it ought to be thought about, and in particular what consent then means." [ 80 ] [ failed verification ]


Socially constructed masculinity might suggest that men are constantly interested in sex, and that once men are sexually aroused, they must be satisfied through orgasm. [ 81 ]  This drive is intertwined with the male identity and consequently creates a momentum that, once started, is difficult to stop. [ 82 ]  Socially constructed femininity might suggest the connotation of passivity, which has affected the cultural importance of female desire. This is a factor that contributes to women's sexual desires being largely ignored; because men are seen as unable to control their sexuality, this can make women responsible for enforcing condom use instead of the "uncontrollable" male. Some scholars argue that a contributing factor in this division of responsibility for safe sex factors is the privileged status of male desire in Western culture, as indicated by the commonly held belief that the female sexual experience is not adversely affected by condom use but that the male sexual experience is diminished with the addition of this barrier. [ 83 ]  They believe that this is problematic, as the use of condoms is symbolically linked to  casual sex  and  promiscuity , which goes against the social norms of femininity. [ 84 ]  This link is considered something that cannot be underestimated as "discontinuation of condom use becomes a test or a marker which signifies the existence of a committed and exclusive relationship," and demonstrates trust. [ 76 ]


Others speculate that the responsibility for condom use falling on women is not so much imposed by society, but is instead resultant of the possible consequences of unprotected sex being generally more serious for women than men (pregnancy, greater likelihood of STI transmission, etc.). Bacterial STIs, such as  chlamydia  and  gonorrhea , show that rates among women can be three times higher than men in high prevalence areas of the United States, and one-fourth of pregnancies in developing countries and one-half of pregnancies in the United States are unintended. [ 85 ]


Another social idea of sexuality is the coital imperative. The coital imperative is the idea that for sex to be real, there must be penile-vaginal intercourse. For many women, this imposes limitations to the sexual possibilities [ 14 ] [ 18 ] [ 63 ]  and a condom is seen as a symbol of the end of the sexual experience. Public acceptance of penis-vagina penetration as central to a sexual relationship is reinforced by the focus on condom use. [ 86 ]  These ideas, male sex drive and coital imperative, paired with the social construction of femininity, may lead to an imbalance of the power in making the decision to use a condom. [ 87 ]


Human male sexuality  encompasses a wide variety of feelings and behaviors.  Men 's feelings of  attraction  may be caused by various physical and social traits of their potential partner. Men's  sexual behavior  can be affected by many factors, including  evolved predispositions , individual  personality ,  upbringing , and  culture . While most men are  heterosexual , and attracted only to  women , there are minorities of  homosexual men  and varying degrees of  bisexual men . [ 1 ] [ 2 ]


Research indicates that men tend to be attracted to young [ 3 ]   women  with bodily symmetry. [ 4 ]  Facial symmetry,  femininity , and averageness are also linked with attractiveness. [ 5 ]  Men typically find  female breasts  attractive [ 5 ]  and this holds true for a variety of cultures. [ 6 ] [ 7 ] [ 8 ]  The pigmentation of nipples and breasts appears to be the most important quality of breast attractiveness. Men rated women with dark nipples and dark areola as significantly more attractive than those with light-colored nipples or areola. [ 9 ]  Breasts of medium cup size were found to be the most attractive, however authors noted that men focused primarily on the coloration of nipples and areola rather than breast size. [ 9 ]


One study found a historical preference for lighter-skinned women. [ 10 ]  However, the accuracy of this research has been questioned by more recent research, which found a preference for women with darker skin tones. [ 11 ]  Experimental studies show that White men are more attracted to women with tanned and light-brown skin, rather than pale women. [ 12 ]  Women in the West believe that men are more attracted to women with tan skin, which likely explain why women are much more likely to tan than men, according to a 2017 study. [ 13 ] [ 14 ]  There is a direct correlation between being tan and self-perceived attractiveness among young women. [ 15 ]


Skin color contrast has been linked to male sexual preferences across many cultures. [ 16 ]  Women tend to have darker eyes and lips than men, especially relative to the rest of their facial features, and this attribute has been associated with female attractiveness and femininity, [ 16 ]  yet it also decreases male attractiveness according to one study. [ 17 ]  Women may use cosmetics such as lipstick and eye shadow to increase their facial color contrast, or to increase the apparent distance between their eyes and eyebrows. [ 16 ]  A 2009 study found that East Asian people had more facial skin contrast than White people, owing to their consistently darker eyes. [ 17 ]


Women with a relatively low  waist-to-hip ratio  (WHR) are considered more attractive. The exact ratio varies among cultures, depending on the WHR of the women in the local culture. In Western cultures, a WHR of 0.70 is preferred.


Other physical factors of attraction include full lips, facial femininity, long, lustrous hair, low  body mass index , and low waist circumference. [ 5 ]  Preference for a slim or a plump body build is culturally variable, but in a predictable manner. In cultures where food is scarce, plumpness is associated with higher status and is more attractive, but the reverse is true in wealthy cultures. [ 5 ]


Men generally prefer their wives to be younger than they are, but by how much exactly varies between cultures. Older men prefer greater age differences, while teenage males prefer females slightly older than they are. [ 5 ]


The exact degree to which physical appearance is considered important in selecting a  long-term mate  varies between cultures. [ 5 ]


When choosing  long-term  partners, both men and women desire those who are intelligent, kind, understanding, and healthy. They also show a preference for partners who have similar values, attitudes, personality, and religious beliefs. [ 5 ]


The importance of premarital  chastity  varies a great deal according to culture, as well as the religious beliefs and sexual orientation of the individual. In Western culture, the importance and value of chastity has generally declined among heterosexual individuals. Among 18 different attributes, chastity was rated 10th most valuable in 1939, but only 17th most valuable in 1990. [ 5 ]


Many factors influence men's sexual behavior. These include evolved tendencies, such as a greater interest in casual sex, as well as individual and social factors related to upbringing, personality, and relationship status.


Compared to women, men have a greater interest in  casual sex . On average, men express a greater desire for a variety of sex partners, let less time elapse before seeking sex, lower their standards dramatically when pursuing  short-term mating , have more  sexual fantasies  and more fantasies involving a variety of sex partners, report having a higher sex drive, find cues to sexual exploitability to be attractive for short-term mating, experience more sexual regret over missed sexual opportunities, have a larger number of  extramarital affairs  and are more likely to seek  hookups  and  friends with benefits , and visit  prostitutes  more often. [ 18 ]


One study has several factors that influence the age of first  sexual intercourse  among youth aged 13–18. Those from families with both parents present, from high socioeconomic backgrounds, who performed better at school, were more religious, who had higher parental expectations, and felt like their parents care, showed much lower levels of sexual activity across all age groups in the study. In contrast, those with higher levels of body pride showed higher levels of sexual activity. [ 19 ]


Males who are in a  committed relationship  have a restricted  sociosexual orientation , and will have different sexual behavior compared to males who have an unrestricted sociosexual orientation. Males with a restricted sociosexual orientation will be less willing to have sex outside of their committed relationship and behave according to their desire for commitment and emotional closeness with their partner. [ 20 ]


Sociosexually restricted males are less likely to approach females who have lower  waist-to-hip ratios  (0.68–0.72), generally rated as more physically attractive. [ 21 ]


Elizabeth Cashdan [ 22 ]  proposed that mate strategies among both genders differ depending on how much  parental investment  is expected of the male, and provided research support for her hypotheses. When men expect to provide a high level of parental investment, they will attempt to attract women by emphasising their ability to invest. In addition, men who expect to invest will be more likely to highlight their chastity and fidelity than men who expect not to invest. Men with the expectation of low parental investment will flaunt their sexuality to women. Cashdan argues the fact the research supports the idea that men expecting to invest emphasise their chastity and fidelity, which is a high-cost strategy (because it lowers reproductive opportunities), suggests that that type of behaviour must be beneficial, or the behaviour would not have been  selected . [ 22 ]


Paternity certainty is the extent to which a male knows or believes that a woman's child is his. [ 23 ]


In polygamous societies, men feel greater sexual jealousy when there is low paternity certainty. [ 24 ]  This is because they do not want to risk wasting time, energy and resources on a child that is not theirs. [ 25 ]


Socio-economic differences between cultures also affect paternity certainty. [ 26 ]  In a "natural fertility" country such as Namibia, 96% of males show sexual jealousy. [ 27 ]


Additionally, there is a greater likelihood of paternity loss and paternity uncertainty when there is a lack of contraceptives. [ 27 ]


Far more men than women commit  rape . [ 28 ]  It may be that rape is a non-adaptive by-product of other evolved mechanisms, such as desire for sexual variety and for sex without investment, sensitivity to sexual opportunities, and a general capacity for physical aggression. [ 29 ]  Masculine gender roles and a sense of general and sexual entitlement, which are usually endorsed in  patriarchal  and  heteronormative  societies, [ 30 ]  predict rape-related attitudes and behaviors in men. [ 31 ]  However, it could be that  evolutionary selection  in the  ancestral environment  in some cases favored males who raped, resulting in rape itself being an  adaptation . [ 32 ]  Scholars from several fields have criticized this idea. [ 33 ]   David Buss  states that clear-cut evidence either way is lacking. [ 29 ]


Sexual orientation refers to one's relative attraction to men, to women, or to both. Most researchers studying sexual orientation focus on patterns of attraction rather than behavior or identity, because culture affects the expression of behavior or identity and it is attraction that motivates behavior and identity, not the other way around. [ 1 ]


Aside from being  heterosexual  or  homosexual , individuals can be any of varying degrees of  bisexual . [ 1 ] [ 34 ]  Bailey  et al.  stated that they expect that in all cultures the vast majority of people are sexually predisposed exclusively to the other sex, with a minority being sexually predisposed to the same sex, whether exclusively or not. [ 1 ]  In Western surveys, about 93% of men identify as completely heterosexual, 4% as mostly heterosexual, 0.5% as more evenly bisexual, 0.5% as mostly homosexual, and 2% as completely homosexual. [ 1 ] [ 34 ]  An analysis of 67 studies found that the lifetime prevalence of sex between men (regardless of orientation) was 3–5% for East Asia, 6–12% for South and South East Asia, 6–15% for Eastern Europe, and 6–20% for Latin America. [ 35 ]  The  World Health Organization  estimates a worldwide prevalence of  men who have sex with men  between 3 and 16%. [ 36 ]


Sexual orientation can be measured via self-report or physiologically. Multiple physiological methods exist, including measurement of penile erection, viewing time,  FMRI , and pupil dilation. In men, these all show a high degree of correlation with self-report measures, [ 1 ]  including men who self report as "mostly straight" or "mostly gay". [ 34 ]


What impact same-sex sexuality has upon one's social identity varies across cultures. The question of precisely how cultures through history conceptualized homosexual desire and behavior is a matter of some debate. [ 37 ] [ 38 ]


In much of the modern world, sexual identity is defined based on the sex of one's partner. In some parts of the world, however, sexuality is often socially defined based on sexual roles, whether one is a penetrator (" top ") or is penetrated (" bottom "). [ 36 ] [ 39 ]


Although no causal theory has yet gained widespread support, there is considerably more evidence supporting nonsocial causes of sexual orientation than social ones, especially for males. This evidence includes the cross-cultural correlation of homosexuality and childhood  gender nonconformity , moderate genetic influences found in  twin studies , evidence for  prenatal hormonal effects  on brain organization, the  fraternal birth order effect , and the finding that in rare cases where infant males were raised as girls due to physical deformity, they nevertheless turned out attracted to females. Hypothesized social causes are supported by only weak evidence, distorted by numerous confounding factors. [ 1 ]  Cross-cultural evidence also leans more toward non-social causes. Cultures that are very tolerant of homosexuality do not have significantly higher rates of it. Homosexual behavior is relatively common among boys in British single-sex boarding schools, but adult Britons who attended such schools are no more likely to engage in homosexual behavior than those who did not. In an extreme case, the  Sambia  ritually require their boys to engage in homosexual behavior during adolescence before they have any access to females, yet most of these boys become heterosexual. [ 40 ] [ 41 ]


It is not fully understood why the genes for homosexuality, or allowing it to develop, whatever they may be, persist in the gene pool. One hypothesis involves  kin selection , suggesting that homosexuals invest heavily enough in their relatives to offset the cost of not reproducing as much directly. This has not been supported by studies in Western cultures, but several studies in  Samoa  have found some support for this hypothesis. Another hypothesis involves  sexually antagonistic  genes, which cause homosexuality when expressed in males but increase reproduction when expressed in females. Studies in both Western and non-Western cultures have found support for this hypothesis. [ 1 ] [ 5 ]


It has been hypothesized that homosexual behavior may itself be an  adaptation  for same-sex affiliation or alliance formation, [ 42 ] [ 43 ]  though this disposition would vary genetically among individuals [ 42 ]  and occur more often when competition for female partners is especially severe. [ 43 ]  Evolutionary psychologist  David Buss  criticized this hypothesis, stating that there is no evidence that most young men in most cultures use homoerotic behavior to establish alliances; instead, the norm is for same-sex alliances to not be accompanied by any sexual activity. [ 5 ]  Additionally, he states that there is no evidence that men who engage in homoerotic behavior do better than other men at forming alliances or ascending in status. [ 5 ]  Other researchers have also criticized it, commenting that the cross-cultural data on sexual practices are sketchy and uneven; that there is no need to assume that homosexual behavior, more than any other sexual behavior, is under direct selection rather than being a neutral byproduct; that the hypothesis ignores the existence of  sexual orientation ; that it contradicts findings that behaviorally homosexual or bisexual men have much lower rates of fatherhood; that primate homosexual behavior is not a uniform phenomenon and varies within and across species; and that since same-sex sexual partners are chosen on the basis of sexual emotion (in contrast to  bonobos , for example), alliances of this kind would only occur as often as mutual sexual attraction, and such variability would seem to indicate a lack of design by natural selection. [ 44 ]


Human sexual activity ,  human sexual practice  or  human sexual behaviour  is the manner in which  humans  experience and express  their sexuality . People engage in a variety of sexual acts, ranging from activities done alone (e.g.,  masturbation ) to acts with another person (e.g.,  sexual intercourse ,  non-penetrative sex ,  oral sex , etc.) [ 1 ]  in varying patterns of frequency, for a wide variety of reasons. Sexual activity usually results in  sexual arousal  and physiological changes in the aroused person, some of which are pronounced while others are more subtle. Sexual activity may also include conduct and activities which are intended to arouse the sexual interest of another or enhance the  sex life  of another, such as strategies to find or attract partners ( courtship  and  display  behaviour), or personal interactions between individuals (for instance,  foreplay  or  BDSM ). Sexual activity may follow sexual arousal.


Human sexual activity has sociological, cognitive,  emotional ,  behavioural  and biological aspects. It involves  personal bonding , sharing emotions, the  physiology  of the  reproductive system ,  sex drive , sexual intercourse, and sexual behaviour in all its forms.


In some cultures, sexual activity is considered acceptable only within  marriage , while  premarital  and  extramarital sex  are  taboo . Some  sexual activities are illegal  either universally or in some countries or subnational jurisdictions, while some are considered contrary to the  norms  of certain societies or cultures. Two examples that are criminal offences in most  jurisdictions  are  sexual assault  and sexual activity with a person below the local  age of consent .


Sexual activity can be classified in a number of ways. The practices may be preceded by or consist solely of  foreplay . [ 2 ]  Acts involving one person ( autoeroticism ) may include  sexual fantasy  or  masturbation . [ 2 ]  If two people are involved, they may engage in vaginal sex,  anal sex ,  oral sex  or  manual sex . [ 2 ]   Penetrative sex  between two people may be described as  sexual intercourse , but definitions vary. If there are more than two participants in a sex act, it may be referred to as  group sex . Autoerotic sexual activity can involve use of  dildos ,  vibrators ,  butt plugs , and other  sex toys , though these devices can also be used with a partner.


Sexual activity can be classified into the  gender  and  sexual orientation  of the participants, as well as by the relationship of the participants. The relationships can be ones of marriage,  intimate partners , casual  sex partners  or  anonymous . Sexual activity can be regarded as  conventional  or as  alternative , involving, for example,  fetishism  or  BDSM  activities. [ 3 ] [ 4 ]


Fetishism can take many forms, including the desire for certain body parts ( partialism ) such as  breasts ,  navels , or  feet . [ 5 ]  The object of desire can be  shoes ,  boots ,  lingerie ,  clothing ,  leather  or rubber items. Some non-conventional autoerotic practices can be dangerous. These include  autoerotic asphyxiation  and  self-bondage . [ 6 ]  The potential for injury or even death that exists while engaging in the partnered versions of these fetishes (choking and  bondage , respectively) becomes drastically increased in the autoerotic case due to the isolation and lack of assistance in the event of a problem. [ 6 ]


Sexual activity that is consensual is sexual activity in which both or all participants agree to take part and are of the age that they can consent. [ 7 ]  If sexual activity takes place under force or duress, it is considered  rape  or another form of  sexual assault . In different cultures and countries, various sexual activities may be lawful or illegal in regards to the age, gender,  marital status  or other factors of the participants, or otherwise contrary to  social norms  or generally accepted  sexual morals . [ 7 ]


In  evolutionary psychology  and  behavioral ecology , human mating strategies are a set of behaviors used by individuals to attract, select, and retain  mates . Mating strategies overlap with  reproductive  strategies, which encompass a broader set of behaviors involving the timing of reproduction and the trade-off between quantity and quality of offspring (see  life history theory ).


Relative to other animals, human mating strategies are unique in their relationship with cultural variables such as the institution of  marriage . [ 8 ]  Humans may seek out individuals with the intention of forming a long-term  intimate relationship , marriage,  casual relationship , or  friendship . The human desire for  companionship  is one of the strongest human drives. It is an innate feature of human nature, and may be related to the  sex drive . The human mating process encompasses the social and cultural processes whereby one person may meet another to assess suitability, the  courtship  process and the process of forming an  interpersonal relationship . Commonalities, however, can be found between humans and nonhuman animals in mating behavior.


The  physiological responses  during  sexual stimulation  are fairly similar for both men and women and there are four phases. [ 9 ]


Sexual dysfunction  is the inability to react emotionally or physically to sexual stimulation in a way projected of the average healthy person; it can affect different stages in the sexual response cycles, which are desire, excitement and orgasm. [ 13 ]  In the media, sexual dysfunction is often associated with men, but in actuality, it is more commonly observed in females (43 percent) than males (31 percent). [ 14 ]


Sexual activity can lower blood pressure and overall stress levels. [ 15 ]  It serves to release tension, elevate mood, and possibly create a profound sense of relaxation, especially in the postcoital period. From a biochemical perspective, sex causes the release of  oxytocin  and endorphins and boosts the immune system. [ 15 ]


People engage in sexual activity for any of a multitude of possible reasons. Although the primary evolutionary purpose of sexual activity is reproduction, research on college students suggested that people have sex for four general reasons:  physical attraction , as a  means to an end , to increase  emotional connection , and to  alleviate insecurity . [ 16 ] [ 17 ]


Most people engage in sexual activity because of pleasure they derive from the  arousal of their sexuality , especially if they can achieve  orgasm . Sexual arousal can also be experienced from  foreplay  and flirting, and from  fetish  or BDSM activities, [ 18 ]  or other  erotic activities . Most commonly, people engage in sexual activity because of the  sexual desire  generated by a person to whom they feel  sexual attraction ; but they may engage in sexual activity for the physical satisfaction they achieve in the absence of attraction for another, as in the case of  casual or social sex . [ 19 ]  At times, a person may engage in a sexual activity solely for the sexual pleasure of their partner, such as because of an obligation they may have to the partner or because of love, sympathy or  pity  they may feel for the partner.


A person may engage in sexual activity for purely monetary considerations, or to obtain some advantage from either the partner or the activity. A man and woman may engage in sexual intercourse with the objective of  conception . Some people engage in hate sex which occurs between two people who strongly dislike or annoy each other. It is related to the idea that opposition between two people can heighten  sexual tension , attraction and interest. [ 20 ]


Research has found that people also engage in sexual activity for reasons associated with  self-determination theory . The self-determination theory can be applied to a sexual relationship when the participants have positive feelings associated with the relationship. These participants do not feel guilty or coerced into the partnership. [ 21 ]  Researchers have proposed the model of self-determined sexual motivation. The purpose of this model is to connect self-determination and sexual motivation. [ 22 ]  This model has helped to explain how people are sexually motivated when involved in self-determined dating relationships. This model also links the positive outcomes, (satisfying the need for autonomy, competence, and relatedness) gained from sexual motivations. [ 22 ]


According to the completed research associated with this model, it was found that people of both sexes who engaged in sexual activity for self-determined motivation had more positive psychological well-being. [ 22 ]  While engaging in sexual activity for self-determined reasons, the participants also had a higher need for fulfillment. When this need was satisfied, they felt better about themselves. This was correlated with greater closeness to their partner and higher overall satisfaction in their relationship. [ 22 ]  Though both sexes engaged in sexual activity for self-determined reasons, there were some differences found between males and females. It was concluded that females had more motivation than males to engage in sexual activity for self-determined reasons. [ 22 ]  Females also had higher satisfaction and relationship quality than males did from the sexual activity. [ 22 ]  Overall, research concluded that psychological well-being, sexual motivation, and sexual satisfaction were all positively correlated when dating couples partook in sexual activity for self-determined reasons. [ 22 ]


The frequency of sexual activity might range from zero to 15 or 20 times a week. [ 23 ]  Frequency of intercourse tends to decline with age. [ 24 ]  Some post- menopausal  women experience decline in frequency of sexual intercourse, while others do not. [ 25 ]  According to the  Kinsey Institute , the average frequency of sexual intercourse in the US for individuals with partners is 112 times per year (age 18–29), 86 times per year (age 30–39), and 69 times per year (age 40–49). [ 26 ]  The rate of sexual activity has been declining in the 21st century, a phenomenon that has been described as a  sex recession .


The age at which adolescents become sexually active varies considerably between different cultures and times. (See  Prevalence of virginity .) The first sexual act of a child or adolescent is sometimes referred to as the  sexualization  of the child, and may be considered a milestone or a change of status, as the loss of  virginity  or innocence. Youth are legally free to have intercourse after they reach the  age of consent .


A 1999 survey of students indicated that approximately 40% of ninth graders across the United States report having had sexual intercourse. This figure rises with each grade. Males are more sexually active than females at each of the grade levels surveyed. Sexual activity of young adolescents differs in ethnicity as well. A higher percentage of African American and Hispanic adolescents are more sexually active than white adolescents. [ 27 ]


Research on sexual frequency has also been conducted solely on female adolescents who engage in sexual activity. Female adolescents tended to engage in more sexual activity due to positive mood. In female teenagers, engaging in sexual activity was directly positively correlated with being older, greater sexual activity in the previous week or prior day, and more positive mood the previous day or the same day as the sexual activity occurred. [ 28 ]  Decreased sexual activity was associated with prior or same day negative mood or menstruation. [ 28 ]


Although opinions differ, researchers suggest that sexual activity is an essential part of humans, and that teenagers need to experience sex. According to a study, sexual experiences help teenagers understand pleasure and satisfaction. [ 29 ]  In relation to hedonic and eudaimonic well-being, it stated that teenagers can positively benefit from sexual activity. The cross-sectional study was conducted in 2008 and 2009 at a rural upstate New York community. Teenagers who had their first sexual experience at age 16 revealed a higher well-being than those who were sexually inexperienced or who became sexually active at age 17. [ 29 ]  Furthermore, teenagers who had their first sexual experience at age 15 or younger, or who had many sexual partners were not negatively affected and did not have associated lower well-being. [ 29 ]


Sexual activity is an innately physiological function, [ 30 ]  but like other physical activity, it comes with risks. There are four main types of risks that may arise from sexual activity:  unwanted pregnancy , contracting a  sexually transmitted infection  (STI), physical injury, and psychological injury.


Any sexual activity that involves the introduction of semen into a woman's vagina, such as during sexual intercourse, or contact of semen with her vulva, may result in a pregnancy. To reduce the risk of unintended pregnancies, some people who engage in penile-vaginal sex may use  contraception , such as  birth control pills , a  condom ,  diaphragms ,  spermicides ,  hormonal contraception  or sterilization. [ 31 ]  The effectiveness of the various contraceptive methods in avoiding pregnancy varies considerably, and depends on the method rather than the user. [ 32 ]


Sexual activity that involves skin-to-skin contact, exposure to an infected person's  bodily fluids  or  mucous membranes [ 33 ]  carries the risk of contracting a sexually transmitted infection. People may not be able to detect that their  sexual partner  has one or more STIs, for example if they are asymptomatic (show no symptoms). [ 34 ] [ 35 ]  The risk of STIs can be reduced by  safe sex  practices, such as using condoms. Both partners may opt to be tested for STIs before engaging in sex. [ 36 ]  The exchange of body fluids is not necessary to contract an infestation of crab lice. Crab lice typically are found attached to hair in the pubic area but sometimes are found on coarse hair elsewhere on the body (for example, eyebrows, eyelashes, beard, mustache, chest, armpits, etc.). Pubic lice infestations (pthiriasis) are spread through direct contact with someone who is infested with the louse. [ 37 ] [ 38 ] [ 39 ]


Some STIs like  HIV/AIDS  can also be contracted by using  IV drug   needles  after their use by an infected person, as well as through childbirth or  breastfeeding . [ 40 ]


Factors such as biological and psychological factors, diseases, mental conditions, boredom with the relationship, and widowhood have been found to contribute to a decrease in sexual interest and activity in old age, but older age does not eliminate the ability to enjoy sexual activity. [ 41 ]


Heterosexuality is the romantic or sexual attraction to the opposite sex. Heterosexual practices are institutionally privileged in most countries. [ 42 ]  In some countries, mostly those where religion has a strong influence on  social policy , marriage laws serve the purpose of encouraging people to have sex only within marriage.  Sodomy laws  have been used to discourage same-sex sexual practices, but they may also affect opposite-sex sexual practices. Laws also ban adults from committing  sexual abuse , committing sexual acts with anyone under an  age of consent , performing sexual activities in public, and engaging in sexual activities for money (prostitution). Though these laws cover both same-sex and opposite-sex sexual activities, they may differ in regard to punishment, and may be more frequently (or exclusively) enforced on those who engage in same-sex sexual activities. [ 43 ]


Different-sex sexual practices may be  monogamous , serially monogamous, or  polyamorous , and, depending on the definition of sexual practice,  abstinent  or  autoerotic  (including  masturbation ). Additionally, different religious and political movements have tried to influence or control changes in sexual practices including courting and marriage, though in most countries changes occur at a slow rate.


Homosexuality is the romantic or sexual attraction to the same sex. People with a homosexual orientation can express their sexuality in a variety of ways, and may or may not express it in their behaviors. [ 44 ]  Research indicates that many gay men and lesbians want, and succeed in having, committed and durable relationships. For example, survey data indicate that between 40% and 60% of gay men and between 45% and 80% of lesbians are currently involved in a romantic relationship. [ 45 ]


It is possible for a person whose sexual identity is mainly heterosexual to engage in sexual acts with people of the same sex. Gay and lesbian people who pretend to be heterosexual are often referred to as being  closeted  (hiding their sexuality in "the closet"). "Closet case" is a derogatory term used to refer to people who hide their sexuality. Making that orientation public can be called " coming out of the closet " in the case of voluntary disclosure or " outing " in the case of disclosure by others against the subject's wishes (or without their knowledge). Among some communities (called "men on the DL" or " down-low "), same-sex sexual behavior is sometimes viewed as solely for physical pleasure.  Men who have sex with men , as well as  women who have sex with women , or men on the "down-low" may engage in sex acts with members of the same sex while continuing sexual and romantic relationships with the opposite sex.


People who engage exclusively in same-sex sexual practices may not identify themselves as gay or lesbian. In sex-segregated environments, individuals may seek relationships with others of their own gender (known as  situational homosexuality ). In other cases, some people may experiment or explore their sexuality with same (or different) sex sexual activity before defining their  sexual identity . Despite stereotypes and common misconceptions, there are no forms of sexual acts exclusive to same-sex sexual behavior that cannot also be found in opposite-sex sexual behavior, except those involving the meeting of the genitalia between same-sex partners –  tribadism  (generally  vulva -to-vulva rubbing) and  frot  (generally  penis -to-penis rubbing).


People who have a romantic or sexual attraction to both sexes are referred to as bisexual. [ 46 ] [ 47 ]  People who have a distinct but not exclusive preference for one sex/gender over the other may also identify themselves as bisexual. [ 48 ]  Like gay and lesbian individuals, bisexual people who pretend to be heterosexual are often referred to as being  closeted .


Pansexuality (also referred to as omnisexuality) [ 49 ]  may or may not be subsumed under bisexuality, with some sources stating that bisexuality encompasses sexual or romantic attraction to all  gender identities . [ 50 ] [ 51 ]  Pansexuality is characterized by the potential for  aesthetic  attraction,  romantic love , or sexual desire towards people without regard for their gender identity or  biological sex . [ 52 ]  Some pansexuals suggest that they are  gender-blind ; that gender and sex are insignificant or irrelevant in determining whether they will be sexually attracted to others. [ 53 ]  As defined in the  Oxford English Dictionary ,  pansexuality "encompasses all kinds of sexuality; not limited or inhibited in sexual choice with regards to gender or practice". [ 54 ]


Although the main adaptive function of human sexual activity is reproduction, human sexual activity also includes the adaptive constraint of avoiding close  inbreeding , since inbreeding can have deleterious effects on progeny.  Charles Darwin, who was married to his first cousin Emma Wedgwood, considered that the ill health that plagued his family was a consequence of inbreeding. [ 55 ]  In general, inbreeding between individuals who are closely genetically related leads to the expression of deleterious recessive  mutations .  The avoidance of inbreeding as a constraint on human sexual activity is apparent in the near universal cultural  inhibitions  in human societies of sexual activity between closely related individuals. [ 56 ]  Human  outcrossing  sexual activity provides the adaptive benefit of the masking of expression of deleterious recessive mutations. [ 57 ]


Alex Comfort  and others propose three potential social aspects of sexual intercourse in humans, which are not mutually exclusive: reproductive, relational, and recreational. [ 58 ]  The development of  the contraceptive pill  and other highly effective forms of  contraception  in the mid- and late 20th century has increased people's ability to segregate these three functions, which still overlap a great deal and in complex patterns. For example: A fertile couple may have intercourse while using contraception to experience sexual pleasure (recreational) and also as a means of emotional intimacy (relational), thus deepening their bonding, making their relationship more stable and more capable of sustaining children in the future (deferred reproductive). This same couple may emphasize different aspects of intercourse on different occasions, being playful during one episode of intercourse (recreational), experiencing deep emotional connection on another occasion (relational), and later, after discontinuing contraception, seeking to achieve pregnancy (reproductive, or more likely reproductive and relational). [ citation needed ]


Human sexual activity is generally influenced by social rules that are culturally specific and vary widely. [ 59 ]


Sexual ethics, morals, and norms relate to issues including deception/honesty, legality,  fidelity  and consent. Some activities, known as  sex crimes  in some locations, are illegal in some jurisdictions, including those conducted between (or among) consenting and competent adults (examples include  sodomy law  and adult-adult  incest ).


Some people who are in a relationship but want to hide polygamous activity (possibly of opposite sexual orientation) from their partner, may solicit consensual sexual activity with others through personal contacts,  online chat rooms , or, advertising in select media.


Swinging  involves singles or partners in a  committed relationship  engaging in sexual activities with others as a  recreational  or social activity. [ 60 ]  The increasing popularity of swinging is regarded by some as arising from the upsurge in sexual activity during the  sexual revolution  of the 1960s.


Some people engage in various sexual activities as a business transaction. When this involves having sex with, or performing certain actual sexual acts for another person in exchange for money or something of value, it is called prostitution. Other aspects of the  adult industry  include  phone sex  operators,  strip clubs , and pornography.


Social  gender roles  can influence sexual behavior as well as the reaction of individuals and communities to certain incidents; the  World Health Organization  states that, "Sexual violence is also more likely to occur where beliefs in male sexual entitlement are strong, where gender roles are more rigid, and in countries experiencing high rates of other types of violence." [ 61 ]  Some societies, such as those where the concepts of  family honor  and female  chastity  are very strong, may practice violent control of female sexuality, through practices such as  honor killings  and  female genital mutilation . [ 62 ] [ 63 ]


The relation between  gender equality  and sexual expression is recognized, and promotion of equity between men and women is crucial for attaining  sexual  and  reproductive health , as stated by the UN  International Conference on Population and Development  Program of Action: [ 64 ]


BDSM is a variety of  erotic  practices or  roleplaying  involving  bondage ,  dominance and submission ,  sadomasochism , and other interpersonal dynamics. [ 60 ]  Given the wide range of practices, some of which may be engaged in by people who do not consider themselves as practicing BDSM, inclusion in the BDSM community or subculture usually being dependent on  self-identification  and shared experience. [ 65 ]  BDSM communities generally welcome anyone with a non-normative streak who identifies with the community; this may include  cross-dressers , extreme  body modification  enthusiasts,  animal players , latex or  rubber aficionados , and others.


B/D (bondage and discipline) is a part of BDSM. Bondage includes the restraint of the body or mind. [ 66 ]  D/s means "Dominant and submissive". A Dominant is one who takes control of a person who wishes to surrender control and a submissive is one who surrenders control to a person who wishes to take control. [ 66 ]  S/M (sadism and masochism) is the other part of BDSM. A sadist is an individual who takes pleasure in the pain or humiliation of others and a masochist is an individual who takes pleasure from their own pain or humiliation. [ 66 ]


Unlike the usual "power neutral" relationships and play styles commonly followed by couples, activities and relationships within a BDSM context are often characterized by the participants' taking on complementary, but unequal roles; thus, the idea of  informed consent  of both the partners becomes essential. Participants who exert dominance (sexual or otherwise) over their partners are known as Dominants or  Tops , while participants who take the passive, receiving, or obedient role are known as submissives or  bottoms .


These terms are sometimes shortened so that a dominant person may be referred to as a "Dom" (a woman may choose to use the feminine "Domme") and a submissive may be referred to as a "sub". Individuals who can change between Top/Dominant and bottom/submissive roles – whether from relationship to relationship or within a given relationship – are known as  switches . The precise definition of roles and self-identification is a common subject of debate within the community. [ 67 ]
In a 2013 study, researchers stated that BDSM is a sexual act where participants play role games, use restraint, use power exchange,
use suppression and pain is sometimes involved depending on individual(s). [ 68 ]  The study serves to challenge the widespread notion that BDSM could be in some way linked to  psychopathology . According to the findings, one who participates in BDSM may have greater strength socially and mentally as well as greater independence than those who do not practice BDSM. [ 68 ]  It suggests that people who participate in BDSM play have higher subjective well-being, and that this might be due to the fact that BDSM play requires extensive communication. Before any act occurs, the partners must discuss their agreement of their relationship. They discuss how long the play will last, the intensity, their actions, what each participant needs or desires, and what, if any, sexual activities may be included. All acts must be consensual and pleasurable to both parties. [ 68 ]


In a 2015 study, interviewed BDSM participants have mentioned that the activities have helped to create higher levels of connection, intimacy, trust and communication between partners. [ 66 ]  The study suggests that Dominants and submissives exchange control for each other's pleasure and to satisfy a need. The participants have remarked that they enjoy pleasing their partner in any way they can and many surveyed have felt that this is one of the best things about BDSM. It gives a submissive pleasure to do things in general for their Dominant while a Dominant enjoys making their encounters all about their submissive and enjoy doing things that makes their submissive happy. The findings indicate that the surveyed submissives and Dominants found BDSM makes play more pleasurable and fun. The participants have also mentioned improvements in their personal growth, romantic relationships, sense of community and self, the dominant's confidence, and their coping with everyday things by giving them a psychological release. [ 66 ]


There are many laws and social customs which prohibit, or in some way affect sexual activities. These laws and customs vary from country to country, and have varied over time. They cover, for example, a prohibition to non-consensual sex, to sex outside marriage, to sexual activity in public, besides many others. Many of these restrictions are non-controversial, but some have been the subject of public debate.


Most societies consider it a serious crime to force someone to engage in sexual acts or to engage in sexual activity with someone who does not consent. This is called  sexual assault , and if sexual penetration occurs it is called rape, the most serious kind of sexual assault. The details of this distinction may vary among different legal jurisdictions. Also, what constitutes effective consent in sexual matters varies from culture to culture and is frequently debated. Laws regulating the minimum age at which a person can consent to have sex ( age of consent ) are frequently the subject of debate, as is  adolescent sexual behavior  in general. Some societies have forced marriage, where consent may not be required.


Many locales have laws that limit or prohibit  same-sex sexual activity .


In the West,  sex before marriage  is not illegal. There are social taboos and many religions condemn pre-marital sex. In many Muslim countries, such as Saudi Arabia, Pakistan, [ 69 ]  Afghanistan, [ 70 ] [ 71 ] [ 72 ]  Iran, [ 72 ]  Kuwait, [ 73 ]  Maldives, [ 74 ]  Morocco, [ 75 ]  Oman, [ 76 ]  Mauritania, [ 77 ]  United Arab Emirates, [ 78 ] [ 79 ]  Sudan, [ 80 ]  and Yemen, [ 81 ]  any form of sexual activity outside marriage is illegal. Those found guilty, especially women, may be forced to wed the sexual partner, may be publicly beaten, or may be stoned to death. [ 82 ]  In many African and native tribes, sexual activity is not viewed as a privilege or right of a married couple, but rather as the unification of bodies and is thus not frowned upon. [ 83 ]


Other studies have analyzed the changing attitudes about sex that American adolescents have outside marriage. Adolescents were asked how they felt about oral and vaginal sex in relation to their health, social, and emotional well-being. Overall, teenagers felt that oral sex was viewed as more socially positive amongst their demographic. [ 84 ]  Results stated that teenagers believed that oral sex for dating and non-dating adolescents was less threatening to their overall values and beliefs than vaginal sex was. [ 84 ]  When asked, teenagers who participated in the research viewed oral sex as more acceptable to their peers, and their personal values than vaginal sex. [ 84 ]


The laws of each jurisdiction set the minimum age at which a young person is allowed to engage in sexual activity. [ 85 ]  This  age of consent  is typically between 14 and 18 years, but laws vary. In many jurisdictions, age of consent is a person's mental or functional age. [ 86 ] [ 87 ] [ 88 ]  As a result, those above the set age of consent may still be considered unable to legally consent due to mental immaturity. [ 86 ] [ 87 ] [ 88 ] [ 89 ] [ 90 ]  Many jurisdictions regard any sexual activity by an adult involving a child as  child sexual abuse .


Age of consent may vary by the type of sexual act, the sex of the actors, or other restrictions such as abuse of a  position of trust . Some jurisdictions also make allowances for young people engaged in sexual acts with each other. [ 91 ]


Most jurisdictions prohibit sexual activity between certain close relatives. These laws vary to some extent; such acts are called  incestuous .


Incest laws may involve restrictions on  marriage  rights, which also vary between jurisdictions. When incest involves an adult and a child, it is considered to be a form of  child sexual abuse . [ 92 ] [ 93 ]


Non-consensual sexual activity or subjecting an unwilling person to witnessing a sexual activity are forms of  sexual abuse , as well as (in many countries) certain non-consensual paraphilias such as  frotteurism ,  telephone scatophilia  (indecent phonecalls), and non-consensual  exhibitionism  and  voyeurism  (known as " indecent exposure " and " peeping tom " respectively). [ 94 ]


People sometimes exchange sex for money or access to other resources. Work takes place under many varied circumstances. The person who receives payment for sexual services is known as a prostitute and the person who receives such services is referred to by a multitude of terms, such as being a  client . Prostitution is one of the branches of the  sex industry . The  legal status of prostitution  varies from  country to country , from being a punishable crime to a regulated profession. Estimates place the annual revenue generated from the global prostitution industry to be over $100 billion. [ 95 ]  Prostitution is sometimes referred to as "the world's oldest profession". [ 96 ]  Prostitution may be a voluntary individual activity or facilitated or  forced  by  pimps .


Survival sex  is a form of prostitution engaged in by people in need, usually when  homeless  or otherwise disadvantaged people trade sex for food, a place to sleep, or other  basic needs , or for  drugs . [ 97 ]  The term is used by  sex trade  and poverty researchers and  aid workers . [ 98 ] [ 99 ]


Human sexuality  covers a broad range of topics, including the physiological, psychological, social, cultural, political, philosophical, ethical, moral, theological, legal and spiritual or religious aspects of sex and human sexual behavior.


Articles pertaining to human sexuality include:


The following  outline  is provided as an overview of and topical guide to human sexuality:


Human sexuality  is the capacity to have  erotic  experiences and responses. [ 1 ]  Human sexuality can also refer to the way one person is sexually attracted to another person of the opposite sex ( heterosexuality ), the same sex ( homosexuality ), or having both tendencies ( bisexuality ). The lack of sexual attraction is referred to as  asexuality . [ 2 ]  Human sexuality impacts cultural, political, legal and philosophical aspects of life, as well as being widely connected to issues of  morality ,  ethics ,  theology ,  spirituality , or  religion . It is not, however, directly tied to  gender . [ citation needed ]


History of human sexuality


Sexual orientation


Human sexual activity


Sex and the law


Sexual assault


Religion and sexuality


Sex industry


The  2001 sex strike for running water  in  Turkey  began when women in a Turkish village initiated a nonviolent direct action to persuade the men of the village to fix a broken water system. [ 1 ]


In 2001, a southern Turkish village near  Siirt  suffered from a broken down water supply system. This was not the first time the system had stopped, leaving the 600-person village without running water for months at a time. When the water system breaks down, the women must walk  several miles to a small public  fountain  in order to have water for drinking, cooking and bathing.


In mid-July 2001, women in the village began a  sex strike  to encourage their husbands to demand that the government repair the water system. The idea of the sex strike came from a Turkish movie from 1983 in which women held a sex strike for better equality between the genders.


The lack of running water prevented women from bathing after sex, which is traditionally required of  Muslim  women. This ritual is known as  ritual purification , which has to do with preparation for prayer that occurs five times a day.


Within one month of the sex strike, the men began asking the Siirt government for assistance to fix the water system. On August 15, the government supplied the village with enough resources to fix the water system themselves.


A film,  The Source , was created in 2011 capturing a similar story in a  North Africa . In the film, the women of the village take part in a sex strike against having to walk to a water source to collect water.


Adultery  is  extramarital sex  that is considered objectionable on social, religious, moral, or legal grounds. Although the  sexual activities  that constitute adultery vary, as well as the social, religious, and legal consequences, the concept exists in many cultures and shares some similarities in  Judaism ,  Christianity  and  Islam . [ 1 ]  Adultery is viewed by many jurisdictions as offensive to public morals, undermining the marriage relationship. [ 2 ] [ 3 ]


Historically , many cultures considered adultery a very serious  crime , some subject to severe punishment, usually for the woman and sometimes for the man, with penalties including  capital punishment ,  mutilation , or  torture . [ 4 ]  Such punishments have gradually fallen into disfavor, especially in  Western countries  from the 19th century. In countries where adultery is still a criminal offense, punishments range from  fines  to  caning [ 5 ]  and even capital punishment. Since the 20th century,  criminal laws  against adultery have become controversial, with most Western countries decriminalising adultery.


However, even in jurisdictions that have decriminalised adultery, it may still have legal consequences, particularly in jurisdictions with fault-based  divorce  laws, where adultery almost always constitutes a  ground for divorce  and may be a factor in  property settlement , the  custody of children , the denial of  alimony , etc. Adultery is not a ground for divorce in jurisdictions which have adopted a  no-fault divorce  model. [ citation needed ]


International organizations [ which? ]  have called for the decriminalisation of adultery, especially in the light of several high-profile  stoning  cases that have occurred in some countries. [ which? ]  The head of the United Nations expert body charged with identifying ways to eliminate laws that discriminate against women or are discriminatory to them in terms of implementation or impact,  Kamala Chandrakirana , has stated that: "Adultery must not be classified as a criminal offence at all". [ 6 ]  A joint statement by the United Nations Working Group on discrimination against women in law and in practice states that: "Adultery as a criminal offence violates women’s human rights". [ 7 ]


In Muslim countries that follow  Sharia law  for criminal justice, the punishment for adultery may be stoning. [ 8 ]  There are fifteen [ 9 ]  countries in which stoning is authorized as lawful punishment, though in recent times it has been legally carried out only in Iran and Somalia. [ 10 ]  Most countries that criminalize adultery are those where the dominant religion is Islam, and several  Sub-Saharan African  Christian-majority countries, but there are some notable exceptions to this rule, namely the Philippines, and several U.S. states. In some jurisdictions, having sexual relations with the king's wife or the wife of his eldest son constitutes  treason . [ 11 ]


The term  adultery  refers to sexual acts between a married person and someone who is not that person's spouse. [ 12 ] [ 13 ] [ 14 ]  It may arise in a number of contexts. In  criminal law , adultery was a criminal offence in many countries in the past, and is still a crime in some countries today. In  family law , adultery may be a  ground for divorce , [ 15 ]  with the legal definition of adultery being "physical contact with an alien and unlawful organ", [ 16 ]  while in some countries today, adultery is not in itself grounds for divorce. Extramarital sexual acts not fitting this definition are not "adultery" though they may constitute "unreasonable behavior", also a ground of divorce.


Another issue is the issue of paternity of a child. The application of the term to the act appears to arise from the idea that "criminal intercourse with a married woman ... tended to adulterate the issue [children] of an innocent husband ... and to expose him to support and provide for another man's [children]". [ 17 ]  Thus, the "purity" of the children of a marriage is corrupted, and the inheritance is altered.


In archaic law, there was a  common law  tort of  criminal conversation  arising from adultery, "conversation" being an archaic euphemism for sexual intercourse. It was a  tort action  brought by a husband against a third party (“the other man”) who interfered with the marriage relationship. [ citation needed ]


Some adultery laws differentiate based on the sex of the participants, and as a result such laws are often seen as discriminatory, and in some jurisdictions they have been struck down by courts, usually on the basis that they discriminated against women. [ 18 ] [ 19 ]


The term  adultery , rather than  extramarital sex , implies a moral condemnation of the act; as such it is usually not a neutral term because it carries an implied judgment that the act is wrong. [ 20 ]


Adultery refers to sexual relations which are not officially legitimized; for example it does not refer to having sexual intercourse with multiple partners in the case of  polygamy  (when a man is married to more than one wife at a time, called  polygyny ; or when a woman is married to more than one husband at a time, called  polyandry ).


In the traditional English  common law , adultery was a  felony . Although the legal definition of  adultery  differs in nearly every legal system, the common theme is  sexual relations  outside of marriage, in one form or another.


Traditionally, many cultures, particularly  Latin American  ones, had strong  double standards  regarding male and female adultery, with the latter being seen as a much more serious violation. [ 22 ] [ 23 ] [ 24 ]


Adultery involving a married woman and a man other than her husband was considered a very serious crime. In 1707, English Lord Chief Justice John Holt stated that a man having sexual relations with another man's wife was "the highest invasion of property" and claimed, in regard to the aggrieved husband, that "a man cannot receive a higher provocation" (in a case of murder or manslaughter). [ 25 ]


The  Encyclopedia of Diderot & d'Alembert , Vol. 1 (1751), also equated adultery to  theft  writing that, "adultery is, after homicide, the most punishable of all crimes, because it is the most cruel of all thefts, and an outrage capable of inciting murders and the most deplorable excesses." [ 26 ]


Legal definitions of adultery vary. For example,  New York  defines an adulterer as a person who "engages in  sexual intercourse  with another person at a time when he has a living spouse, or the other person has a living spouse." [ 27 ]   North Carolina  defines adultery as occurring when any man and woman "lewdly and lasciviously associate, bed, and cohabit together." [ 28 ]
 Minnesota  law (repealed in 2023) [ 29 ]  provided: "when a married woman has sexual intercourse with a man other than her husband, whether married or not, both are guilty of adultery." [ 30 ]  In the 2003  New Hampshire Supreme Court  case  Blanchflower v. Blanchflower , it was held that  female same-sex sexual relations  did not constitute sexual intercourse, based on a 1961 definition from  Webster's Third New International Dictionary ; and thereby an accused wife in a divorce case was found not guilty of adultery. In 2001,  Virginia  prosecuted an attorney, John R. Bushey, for adultery, a case that ended in a guilty plea and a $125 fine. [ 31 ] [ 32 ]  Adultery is against the  governing law of the U.S. military . [ 33 ]


In  common-law  countries, adultery was also known as  criminal conversation .  This became the name of the civil  tort  arising from adultery, being based upon compensation for the other spouse's injury. [ 34 ]  Criminal conversation was usually referred to by lawyers as  crim. con. , and was abolished in  England  in 1857, and the  Republic of Ireland  in 1976. Another tort,  alienation of affection , arises when one spouse deserts the other for a third person. [ 35 ]  This act was also known as desertion, which was often a crime as well. [ 36 ]  A small number of jurisdictions still allow suits for criminal conversation and/or alienation of affection. [ 37 ]  In the United States, six states still maintain this tort. [ 38 ] [ 39 ]


A marriage in which both spouses agree ahead of time to accept sexual relations by either partner with others is sometimes referred to as an  open marriage  or the  swinging  lifestyle.  Polyamory , meaning the practice, desire, or acceptance of intimate relationships that are not exclusive with respect to other sexual or intimate relationships, with knowledge and consent of everyone involved, sometimes involves such marriages. Swinging and open marriages are both a form of  non-monogamy , and the spouses would not view the sexual relations as objectionable. However, irrespective of the stated views of the partners, extramarital relations could still be considered a crime in some legal jurisdictions which criminalize adultery.


In Canada, though the written definition in the  Divorce Act  refers to extramarital relations with someone of the opposite sex, a  British Columbia  judge used the  Civil Marriage Act  in a 2005 case to grant a woman a divorce from her husband who had cheated on her with another man, which the judge felt was equal reasoning to dissolve the union.


In England and Wales, case law restricts the definition of adultery to penetrative sexual intercourse between a man and a woman, no matter the gender of the spouses in the marriage.  Infidelity  with a person of the same gender can be grounds for a divorce as unreasonable behavior; this situation was discussed at length during debates on the  Marriage (Same-Sex Couples) Bill . [ 40 ]  However, the practical effect of this ceased with the introduction of no-fault divorce in April 2022, which meant that unreasonable behavior ceased to be grounds for divorce.


In India,  adultery  was the sexual intercourse of a man with a married woman without the consent of her husband when such sexual intercourse did not amount to rape, and it was a non-cognizable, non-bailable criminal offence; the adultery law was overturned by the Supreme Court of India on 27 September 2018. [ 41 ]


Durex 's Global Sex Survey found that worldwide 22% of people surveyed admitted to have had extramarital sex. [ 42 ] [ 43 ]  According to a 2015 study by Durex and Match.com, Thailand and Denmark were the most adulterous countries based on the percentage of adults who admitted having an affair. [ 44 ] [ 45 ]


In the United States  Alfred Kinsey  found in his studies that 50% of males and 26% of females had extramarital sex at least once during their lifetime. [ 46 ]  Depending on studies, it was estimated that 22.7% of men and 11.6% of women, had extramarital sex. [ 47 ]  Other authors say that between 20% and 25% of Americans had sex with someone other than their spouse. [ 48 ]


Three 1990s studies in the United States, using nationally representative samples, have found that about 10–15% of women and 20–25% of men admitted to having engaged in  extramarital sex . [ 47 ] [ 49 ] [ 50 ]


The  Standard Cross-Cultural Sample  described the occurrence of extramarital sex by gender in over 50 pre-industrial cultures. The occurrence of extramarital sex by men is described as "universal" in 6 cultures, "moderate" in 29 cultures, "occasional" in 6 cultures, and "uncommon" in 10 cultures. The occurrence of extramarital sex by women is described as "universal" in 6 cultures, "moderate" in 23 cultures, "occasional" in 9 cultures, and "uncommon" in 15 cultures. [ 51 ] [ 52 ]


In the  Greco-Roman world , there were stringent laws against adultery, but these applied to sexual intercourse with a married woman. In the early  Roman Law , the  jus tori  belonged to the husband. It was therefore not illegal for a  husband  to have sex with a slave or an unmarried woman. [ 53 ] [ 54 ]


The Roman husband often took advantage of his legal immunity. Thus historian  Spartianus  said that  Verus , the imperial colleague of  Marcus Aurelius , did not hesitate to declare to his reproaching wife: "Uxor enim dignitatis nomen est, non voluptatis." (' Wife' connotes rank, not sexual pleasure , or more literally "Wife is the name of dignity, not bliss") (Verus, V).


Later in Roman history, as William E.H. Lecky has shown, the idea that the husband owed a fidelity similar to that demanded of the wife must have gained ground, at least in theory. Lecky gathers from the  legal maxim  of  Ulpian : "It seems most unfair for a man to require from a wife the chastity he does not himself practice". [ 55 ]


According to  Plutarch , the lending of wives practiced among some people was also encouraged by  Lycurgus , though from a motive other than that which actuated the practice (Plutarch, Lycurgus, XXIX). The recognized license of the Greek husband may be seen in the following passage of the  pseudo-Demosthenic   Oration Against Neaera :


The Roman  Lex Julia ,  Lex Iulia de Adulteriis Coercendis  (17 BC), punished adultery with banishment. [ 56 ]  The two guilty parties were sent to different islands ("dummodo in  diversas  insulas relegentur"), and part of their property was confiscated. [ 56 ]  Fathers were permitted to kill daughters and their partners in adultery. Husbands could kill the partners under certain circumstances and were required to divorce adulterous wives.


Both Judaism and Christianity base their injunction against adultery on passages in the  Hebrew Bible  ( Old Testament  in Christianity), which firstly prohibits adultery in the  Seventh Commandment : "Thou shalt not commit adultery."
( Exodus 20:12 ). However, Judaism and Christianity differ on what actually constitutes adultery.


Leviticus 20:10  defines what constitutes adultery in the Hebrew Bible, and it also prescribes the punishment as  capital punishment . In this verse, and in the Jewish tradition, adultery consists of sexual intercourse between a man and a  married  woman who is not his lawful wife:


And the man that committeth adultery with another man's wife, even he that committeth adultery with his neighbour's wife, the adulterer and the adulteress shall surely be put to death.


Thus, according to the Hebrew Bible, adultery is not committed if the female participant is unmarried (unless she is  betrothed  to be married [ 57 ] ), while the marital status of the male participant is irrelevant (he himself could be married or unmarried to another woman).


If a married woman was raped by a man who is not her husband, only the rapist is punished for adultery. The victim is not punished: as the Bible declares, "this matter is similar to when a man rises up against his fellow and murders him"; just as a murder victim is not guilty of murder, a rape victim is not guilty of adultery. [ 58 ]


Michael Coogan  writes that according to the text wives are the property of their husband, marriage meaning transfer of property (from father to husband), [ 59 ]  and adultery is violating the property right of the husband. [ 59 ]  However, in contrast to other ancient Near Eastern law collections which treat adultery as an offense against the husband alone, and allow the husband to waive or mitigate the punishment, Biblical law allows no such mitigation, on the grounds that God as well as the husband is offended by adultery, and an offense against God cannot be forgiven by man. [ 60 ]  In addition, Coogan's book was criticized by  Phyllis Trible , who argues that that  patriarchy  was not decreed, but only described by God. [ 61 ]  She claims that  Paul the Apostle  made the same mistake as Coogan. [ 61 ]


David 's sexual intercourse with  Bathsheba , the wife of  Uriah , is described by the Bible as a "sin" [ 62 ]  whose punishment included the ravishment of David's own wives. [ 63 ]  According to Jennifer Wright Knust, David's act was adultery only according to the spirit and not the letter of the law, because Uriah was non-Jewish, and (according to Knust) the Biblical codes only technically applied to Israelites. [ 64 ]  However, according to  Jacob Milgrom , Jews and resident foreigners received equal protection under Biblical law. [ 65 ]  In any case, according to the Babylonian Talmud, Uriah was indeed Jewish [ 66 ] [ 67 ]  and wrote a provisional  bill of divorce  prior to going out to war, specifying that if he fell in battle, the divorce would take effect from the time the writ was issued. [ 68 ] [ 69 ]


Though Leviticus 20:10 prescribes the death penalty for adultery, the legal procedural requirements were very exacting and required the testimony of two eyewitnesses of good character for conviction. The defendant also must have been warned immediately before performing the act. [ 70 ]  A death sentence could be issued only during the period when the  Holy Temple  stood, and only so long as the  Sanhedrin  court convened in its chamber within the Temple complex. [ 71 ]  Technically, therefore, no death penalty can now be applied. [ 72 ]


The death penalty for adultery was generally strangulation, [ 73 ]  except in the case of a woman who was the  daughter of a Kohen , which was specifically mentioned in Scripture as the penalty of burning (pouring molten lead down the throat), [ 74 ]  or a woman who was betrothed but not married, in which case the punishment for both man and woman was stoning. [ 75 ]


At the civil level,  Jewish law  (halakha) forbids a man to continue living with an adulterous wife, and he is obliged to divorce her. Also, an adulteress is not permitted to marry the adulterer, but (to avoid any doubt as to her status as being free to marry another or that of her children) many authorities say he must give her a divorce as if they were married. [ 76 ]


According to Judaism, the  Seven laws of Noah  apply to all of humankind; these laws prohibit adultery to non-Jews as well as Jews. [ 77 ]


The extramarital intercourse of a married man is not in itself considered a crime in biblical or later Jewish law; [ 78 ] [ 79 ]  it was considered akin to  polygyny , which was permitted. Similarly, sexual intercourse between an unmarried man and a woman who was neither married nor  betrothed  was not considered adultery. [ 79 ]  This concept of adultery stems from the economic aspect of Israelite marriage whereby the husband has an exclusive right to his wife, whereas the wife, as the husband's possession, did not have an exclusive right to her husband. [ 80 ]


Adultery is considered immoral by Christians and a  sin , based primarily on passages like  Exodus 20:14  and  1 Corinthians 6:9–10 . Although  1 Corinthians 6:11  does say that "and that is what some of you were. But you were washed", it still acknowledges adultery to be immoral and a sin.


Catholicism  ties  fornication  with breaking the  sixth commandment  in its  Catechism . [ 81 ]


Until a few decades ago, [ when? ]  adultery was a criminal offense in many countries where the dominant religion is Christianity, especially in  Roman Catholic  countries (for example, in  Austria  it was a criminal offense until 1997 [ 82 ] ). Adultery was decriminalized in  Chile  in 1994, [ 83 ]   Argentina  in 1995, [ 84 ]   Brazil  in 2005 [ 85 ]  and  Mexico  in 2011, [ 86 ] [ 87 ]  but in some predominantly Catholic countries, such as the Philippines, it remains illegal.


The  Book of Mormon  also prohibits adultery. For instance, Abinadi cites the  Ten Commandments  when he accuses  King Noah 's priests of sexual immorality. [ 88 ]  When  Jesus Christ  visits the Americas he reinforces the law and teaches them the higher law (also found in the  New Testament ):


Some churches such as  the Church of Jesus Christ of Latter-day Saints  have interpreted "adultery" to include  all sexual relationships outside of marriage , regardless of the marital status of the participants. [ 90 ]   Book of Mormon   prophets  and civil leaders often list adultery as an illegal activity along with murder, robbing, and stealing. [ 91 ]


Zina'  is an Arabic term for illegal intercourse, premarital or extramarital. Various conditions and punishments have been attributed to adultery. Under  Islamic law , adultery in general is sexual intercourse by a person (whether man or woman) with someone to whom they are not married. Adultery is a violation of the marital contract and one of the major sins condemned by God in the  Qur'an : [ 92 ]


Qur'anic verses prohibiting adultery include:


Do not go near adultery. It is truly a shameful deed and an evil way.


Say, “My Lord has only forbidden open and secret indecencies, sinfulness, unjust aggression, associating ˹others˺ with Allah ˹in worship˺—a practice He has never authorized—and attributing to Allah what you do not know.”


Punishments are reserved to the legal authorities and false accusations are to be punished severely. [ 93 ]  It has been said that these legal procedural requirements were instituted to protect women from  slander  and false accusations: i.e. four witnesses of good character are required for conviction, who were present at that time and saw the deed taking place; and if they saw it they were not of good moral character, as they were looking at naked adults; thus no one can be convicted of adultery unless both of the accused also agree and give their confession under oath four times. [ 94 ]


According to  a  hadith  attributed to Muhammad, an unmarried person who commits adultery or fornication is punished by flogging 100 times; a married person will then be  stoned  to death. [ 95 ]  A survey conducted by the  Pew Research Center  found support for stoning as a punishment for adultery mostly in  Arab countries ; it was supported in  Egypt  (82% of respondents in favor of the punishment) and  Jordan  (70% in favor), as well as  Pakistan  (82% favor), whereas in  Nigeria  (56% in favor) and in  Indonesia  (42% in favor) opinion is more divided, perhaps due to diverging traditions and differing interpretations of Sharia. [ 96 ]


The Hindu Sanskrit texts present a range of views on adultery, offering widely differing positions. [ 97 ] [ 98 ]  The hymn 4.5.5 of the  Rigveda  calls adultery as  pāpa  (evil, sin). [ 99 ] [ 100 ]  Other Vedic texts state adultery to be a sin, just like murder, incest, anger, evil thoughts and trickery. [ 101 ]  The Vedic texts, including the  Rigveda , the  Atharvaveda  and the  Upanishads , also acknowledge the existence of male lovers and female lovers as a basic fact of human life, followed by the recommendation that one should avoid such extra marital sex during certain ritual occasions ( yajna ). [ 97 ]  A number of simile in the Rigveda, a woman's emotional eagerness to meet her lover is described, and one hymn prays to the gods that they protect the embryo of a pregnant wife as she sleeps with her husband and other lovers. [ 97 ]


Adultery and similar offenses are discussed under one of the eighteen  vivādapadas  (titles of laws) in the  Dharma  literature of Hinduism. [ 102 ]  Adultery is termed as  Strisangrahana  in  dharmasastra  texts. [ 103 ]  These texts generally condemn adultery, with some exceptions involving consensual sex and  niyoga  (levirate conception) in order to produce an heir. [ 104 ] [ 105 ]  According to  Apastamba Dharmasutra , the earliest dated Hindu law text, cross-varna adultery (adultery across castes) is a punishable crime, where the adulterous man receives a far more severe punishment than the adulterous  arya  woman. [ 106 ]  In  Gautama Dharmasutra , the adulterous  arya  woman is liable to harsh punishment for the cross-class adultery. [ 106 ]  While  Gautama Dharmasutra  reserves the punishment in cases of cross-class adultery, it seems to have been generalized by  Vishnu Dharmasastra  and  Manusmiriti . [ 107 ]  The recommended punishments in the text also vary between these texts. [ 107 ]


The  Manusmriti , also known as the  Laws of Manu , deals with this in greater detail. When translated, verse 4.134 of the book declares adultery to be a heinous offense. [ 108 ]  The  Manusmriti  does not include adultery as a "grievous sin", but includes it as a "secondary sin" that leads to a loss of caste. [ 109 ]  In the book, the intent and mutual consent are a part that determine the recommended punishment. Rape is not considered as adultery for the woman, while the rapist is punished severely. Lesser punishment is recommended for consensual adulterous sex. [ 106 ]  Death penalty is mentioned by Manu, [ 110 ]  as well as "penance" for the sin of adultery. [ 109 ] [ 111 ]  even in cases of repeated adultery with a man of the same caste. [ 112 ]  In verses 8.362-363, the author states that sexual relations with the wife of traveling performer is not a sin, and exempts such sexual liaisons. [ 113 ] [ 114 ]  The verse 5.154 of  Manusmirti  says a woman must constantly worship her husband as a god and be completely faithful even if he commits adultery. [ 115 ] [ 116 ] [ 117 ] [ 118 ]  The book offers two views on adultery. It recommends a new married couple to remain sexually faithful to each other for life. It also accepts that adulterous relationships happen, children are born from such relationships and then proceeds to reason that the child belongs to the legal husband of the pregnant woman, and not to the biological father. [ 119 ]


Other  dharmasastra  texts describe adultery as a punishable crime but offer differing details. [ 107 ]  According to  Naradasmriti (12.61-62) , it is an adulterous act if a man has sexual intercourse with the woman who is protected by another man. The term adultery in  Naradasmriti  is not confined to the relationship of a married man with another man's wife. It includes sex with any woman who is protected, including wives, daughters, other relatives, and servants. Adultery is not a punishable offence for a man if "the woman's husband has abandoned her because she is wicked, or he is eunuch, or of a man who does not care, provided the wife initiates it of her own volition". [ 120 ]  Adultery is not a punishable offence if a married man engages in intercourse with woman who doesn't belong to other man and is not a Brahmin, provided the woman is not of higher caste than the man. [ 121 ]  Brihaspati-smriti mention, among other things, adulterous local customs in ancient India and then states, "for such practices these (people) incur neither penance nor secular punishment". [ 122 ]  Kautilya's  Arthashastra  includes an exemption that in case the husband forgives his adulterous wife, the woman and her lover should be set free. If the offended husband does not forgive, the  Arthashastra  recommends the adulterous woman's nose and ears be cut off, while her lover be executed. [ 123 ]


In  Kamasutra  which is not a religious text like  Vedas  or  Puranas  but an ancient text on love and sex, [ 124 ]  Vatsyayana discusses adultery and devotes "not less than fifteen sutras (1.5.6–20) to enumerating the reasons ( karana ) for which a man is allowed to seduce a married woman". [ 125 ]  According to Wendy Doniger, the  Kamasutra  teaches adulterous sexual liaison as a means for a man to predispose the involved woman in assisting him, working against his enemies and facilitating his successes. It also explains the many signs and reasons a woman wants to enter into an adulterous relationship and when she does not want to commit adultery. [ 126 ]  The  Kamasutra  teaches strategies to engage in adulterous relationships, but concludes its chapter on sexual liaison stating that one should not commit adultery because adultery pleases only one of two sides in a marriage, hurts the other, it goes against both  dharma  and  artha . [ 123 ]


According to Werner Menski, the Sanskrit texts take "widely different positions on adultery", with some considering it a minor offense that can be addressed with penance, but others treat it as a severe offense that depending on the caste deserves the death penalty for the man or the woman. [ 98 ]  According to Ramanathan and Weerakoon, in Hinduism, the sexual matters are left to the judgment of those involved and not a matter to be imposed through law. [ 127 ]


According to Carl Olsen, the classical Hindu society considered adultery as a sexual transgression but treated it with a degree of tolerance. [ 128 ]  It is described as a minor transgression in  Naradasmriti  and other texts, one that a sincere penance could atone. [ 128 ] [ 129 ]  Penance is also recommended to a married person who does not actually commit adultery, but carries adulterous thoughts for someone else or is thinking of committing adultery. [ 130 ]


Other Hindu texts present a more complex model of behavior and mythology where gods commit adultery for various reasons. For example,  Krishna  commits adultery and the  Bhagavata Purana  justifies it as something to be expected when Vishnu took a human form, just like sages become uncontrolled. [ 131 ]  According to Tracy Coleman, Radha and other gopis are indeed lovers of Krishna, but this is  prema  or "selfless, true love" and not carnal craving. In Hindu texts, this relationship between gopis and Krishna involves secret nightly rendezvous. Some texts state it to be divine adultery, others as a symbolism of spiritual dedication and religious value. [ 132 ]  The example of Krishna's adulterous behavior has been used by Sahajiyas Hindus of Bengal to justify their own behavior that is contrary to the mainstream Hindu norm, according to Doniger. [ 131 ]  Other Hindu texts state that Krishna's adultery is not a license for other men to do the same, in the same way that men should not drink poison just because Rudra-Shiva drank poison during the Samudra Manthan. [ 131 ]  A similar teaching is found in Mahayana Buddhism, states Doniger. [ 131 ]


The  Linga Purana  indicates that sexual hospitality existed in ancient India. The sage Sudarshana, asks his wife Oghavati to please their guests in this way. One day, he comes home while she is having sex with a mendicant who visits their house. Sudarshana tells them to continue. The mendicant turns out to be Dharma, the lord of righteous conduct, who blesses the couple for their upholding of social law. [ 133 ] [ 134 ]


Buddhist texts such as  Digha Nikāya  describe adultery as a form of sexual wrongdoing that is one link in a chain of immorality and misery. According to Wendy Doniger, this view of adultery as evil is postulated in early Buddhist texts as having originated from greed in a  previous life . This idea combines Hindu and Buddhist thoughts then prevalent. [ 135 ]   Sentient beings  without body, state the  canonical texts , are reborn on earth due to their greed and craving, some people become beautiful and some ugly, some become men and some women. The ugly envy the beautiful and this triggers the ugly to commit adultery with the wives of the beautiful. Like in  Hindu mythology , states Doniger, Buddhist texts explain adultery as a result from sexual craving; it initiates a degenerative process. [ 135 ]


Buddhism considers celibacy as the monastic ideal. For he who feels that he cannot live in celibacy, it recommends that he never commit adultery with another's wife. [ 136 ]  Engaging in sex outside of marriage, with the wife of another man, with a girl who is engaged to be married, or a girl protected by her relatives (father or brother), or extramarital sex with prostitutes, ultimately causes suffering to other human beings and oneself. It should be avoided, state the Buddhist canonical texts. [ 136 ]


Buddhist Pali texts narrate legends where the Buddha explains the karmic consequences of adultery. For example, states Robert Goldman, one such story is of Thera Soreyya. [ 137 ]  Buddha states in the Soreyya story that "men who commit adultery suffer hell for hundreds of thousands of years after rebirth, then are reborn a hundred successive times as women on earth, must earn merit by "utter devotion to their husbands" in these lives, before they can be reborn again as men to pursue a monastic life and liberation from  samsara . [ 137 ] [ 138 ]


There are some differences between the Buddhist texts and the Hindu texts on the identification and consequences of adultery. According to José Ignacio Cabezón, for example, the Hindu text  Naradasmriti  considers consensual extra-marital sex between a man and a woman in certain circumstances (such as if the husband has abandoned the woman) as not a punishable crime, but the Buddhist texts "nowhere exculpate" any adulterous relationship. The term adultery in  Naradasmriti  is broader in scope than the one in Buddhist sources. In the text, various acts such as secret meetings, exchange of messages and gifts, "inappropriate touching" and a false accusation of adultery, are deemed adulterous, while Buddhist texts do not recognize these acts under adultery. [ 139 ]  Later texts such as the  Dhammapada ,  Pancasiksanusamsa Sutra  and a few Mahayana sutras state that "heedless man who runs after other men's wife" acquire demerit, blame, discomfort and are reborn in hell. [ 140 ]  Other Buddhist texts make no mention of legal punishments for adultery. [ 139 ]


In some Native American cultures, severe penalties could be imposed on an adulterous wife by her husband. In many instances she was made to endure a bodily mutilation which would, in the mind of the aggrieved husband, prevent her from ever being a temptation to other men again. [ 141 ] [ 142 ]  Among the  Aztecs , wives caught in adultery were occasionally impaled, although the more usual punishment was to be stoned to death. [ 143 ]


The  Code of Hammurabi , a well-preserved  Babylonian   law code  of ancient  Mesopotamia , dating back to about 1772 BC, provided  drowning  as punishment for adultery. [ 144 ]


Amputation of the nose –  rhinotomy  – was a punishment for adultery among many civilizations, including ancient India, ancient Egypt, among Greeks and Romans, and in Byzantium and among the Arabs. [ 145 ]


In the tenth century, the Arab explorer  Ibn Fadlan  noted that adultery was unknown among the pagan  Oghuz Turks . Ibn Fadlan writes that "adultery is unknown among them; but whomsoever they find by his conduct that he is an adulterer, they tear him in two. This comes about so: they bring together the branches of two trees, tie him to the branches and then let both trees go, so that he is torn in two." [ 146 ]


In medieval Europe, early Jewish law mandated stoning for an adulterous wife and her partner. [ 147 ]