Why do humans have sex?

Humans have sex in order to reproduce, but hardly anyone would say that this is the only reason for it. What might be the other reasons? Most people would say that pleasure is an important motivation. Relieving sexual tension is another obvious reason. So we’re up to three, all of which concern physical and biological features of sex. Clearly, however, sex is about more than just the physical; there are emotional and psychological factors at work too. It is not hard, therefore, to think of some other likely reasons: to express love; to affirm a bond; to please a partner; to boost one’s own confidence. The more we think about the question, the more we are likely to find the number of reasons growing. For example, people have sex to make money, or to gain experience, or to hurt somebody, or to get revenge, or because they were coerced, or because they were simply bored.

Indeed, the number of reasons why humans have sex is almost certainly much higher than would initially be assumed—237 according to recent research by two American psychologists, Cindy Meston and David Buss, based on studies conducted at the University of Texas. The list of reasons makes for fascinating reading. Alongside the common reasons—pleasure and reproduction, for example—are many others that reveal just how psychologically complex sex is. Among them are:

‘I wanted to intensify my relationship’; ‘I wanted to feel young’; ‘I was drunk’; ‘My regular partner is “boring”, so I had sex with someone else’; ‘I wanted to break up another’s relationship’; ‘I wanted to burn calories’; ‘I wanted to get rid of a headache’; ‘I wanted to welcome someone home’; ‘I wanted to get a promotion’; ‘I wanted to say “I’m sorry”’; ‘I wanted to get the most out of life’; ‘The person was famous and I wanted to be able to say I had sex with him/her’; ‘I was married and you’re supposed to’; ‘I wanted to increase the number of sex partners I had experienced’; ‘I wanted to defy my parents’; ‘I wanted to give someone else a sexually transmitted disease’; ‘Because of a bet’; ‘I wanted to punish myself’; ‘I didn’t know how to say “no”’; ‘Everyone else was having sex’; ‘It’s considered “taboo” by society’; ‘I wanted to “gain control” of the person’; ‘I wanted to feel closer to God’.

Meston and Buss organized the 237 reasons into four large factors and thirteen subfactors: physical reasons (stress reduction, pleasure, physical desirability, experience seeking); goal attainment (resources, social status, revenge, utilitarian); emotional (love and commitment, expression); and insecurity (self-esteem boost, duty/pressure, mate guarding). They also correlated the reasons with psychometric data of the participants in the studies in order to ascertain differences, such as between men and women, in the expressed reasons for having sex. For example, their findings seemed to support some gender stereotypes: men were more likely to state physical attractiveness, opportunity and experience-seeking as reasons; women were more likely to express emotional motivations for having sex. On the other hand, some traditional assumptions were contradicted: Meston and Buss found that more men than women had utilitarian reasons for sex, such as ‘to change the topic of conversation’, ‘to get a favour from someone’, or ‘to improve my sexual skills’, challenging the stereotype that women are more likely to use sex to obtain favours or special treatment.

The study is therefore valuable as evidence for the psychological complexity of human sexual behaviour. It supports the view that humans adopt various sexual and mating strategies, encompassing long-term (e.g. romantic partnerships), short-term (e.g. casual sex) and extra-pair mating. Within these strategies any one of the factors and subfactors may provide reasons to have sex.

Perhaps the greatest value of the study for historians of sex is the recognition by Meston and Buss that sex occurs within a social and cultural context, i.e. it cannot be viewed solely as an act between two (or more) individuals. As they state:

[The] broader social and cultural context [has] implications for prestige, status, and reputation. Having sex with a high status individual, for example, might raise a person’s status within the group. Within some groups, having sex with numerous partners might enhance a person’s reputation, providing the motivational impetus for initiating sex. Sex, of course, can sometimes damage a person’s status and reputation, providing reasons for avoiding it or concealing it from others in the group. In sum, because sex has consequences for status and reputation that can act as incentives (or deterrents), a person might be motivated to have sex for social reasons that have nothing to do with the personal relationship within which it occurs. (p. 478)

Society and culture change over time; hence the social and cultural context of sexual activity also changes over time. Different notions of social prestige, status and reputation can be found in, for example, ancient Greece, seventeenth-century England and twenty-first century America. Similarly, the cultural understanding of marriage, gender relations, love and reproduction varies widely over time and place. It is likely, therefore, that sexual motivations and behaviour has also varied widely in accordance with the different societies and cultures within which they occur.

The reasons for having sex are multifaceted and rarely straightforward. The psychological study of sex tends to confirm this. As a complex area of human behaviour there are clearly good reasons why historians should study it. Moreover, by studying sex in history our understanding of this behaviour—the way it may vary, for example, according to age, gender, social status, or cultural background—will almost certainly increase.

Further reading

Cindy M. Meston and David M. Buss, ‘Why Humans Have Sex’, Archives of Sexual Behavior, 36 (2007), pp. 477-507

Cindy M. Meston and David M. Buss, Why Women Have Sex: Understanding Sexual Motivations from Adventure to Revenge (and Everything in Between) (London: Vintage, 2009)