Results from a new British sex survey, drawing on responses from over 15,000 individuals aged 16-74, have just been made available among in press articles in the journal The Lancet. This study marks the third such British sex survey, also enabling a look into changes across the past two decades in sexual behavior. Architects of the study, Kaye Wellings and Anne M Johnson, also provided a “Comment” piece to advocate for ways in which to frame findings from the study.
In that comment piece, Wellings and Johnson state, “Locating sex within the context of procreation might be easier to deal with, but sexual activity is not primarily, or even necessarily, about reproduction. Sex is more often recreational and communicational than procreational, and is increasingly recognized as such. In a growing number of contexts globally, the separation of sexual activity from reproduction is well under way as contraception, abortion, and assisted reproduction have weakened the natural link. Sexual behaviours that are not essential to conception have become easier to discuss and have gained greater acceptance; they include masturbation, oral and anal sex, same-sex practices, and sex in groups among whom reproduction may not be possible or might have conventionally been deemed inappropriate. In many cultural contexts, what was once seen as deviance or perversion is increasingly referred to as diversity.” (p. 3)
From an evolutionary perspective, does it make sense to talk about sex without reproduction? The nuts and bolts of reproductive anatomy and physiology are most readily understood when asking how their design might enhance reproductive success. As examples, sperm ejaculated during intercourse somehow disproportionately travel toward the ovary from which an egg has been released, and cycle-related changes in cervical mucus appear designed to adaptively let substances in (e.g., sperm) or out (e.g., menstrual blood). Many features of human mating behavior also appear to be best illuminated when seen in reproductive light. Why females might prefer higher status mates, why male attractiveness evaluations orient toward reproductively-related fat distribution, and why males and females alike tend to feature mate preferences indicative of long-term compatibility are all sensible when seen in the light of recent ancestral reproductive relationships. Let’s not throw the baby out with the bathwater.
But in many other ways, Wellings and Johnson are spot on to recognize that human sex is less and less about procreation. In a massive international study of sociosexuality, David Schmitt and colleagues observed differences across countries in how open or restricted individuals were to sex. One of the best predictors of national variation in sociosexuality was fertility: countries with higher fertility tended to have more restricted sociosexuality. Importantly, most countries have undergone declines in fertility in recent decades, which is arguably central to any comment that sex is increasingly unhinged from procreation. In the concluding pages of “Evolution and Human Sexual Behavior,” Justin Garcia and I noted, “More and more people in more and more parts of the world are having fewer and fewer children. About one-third of the world’s countries are having fewer children than replacement…Continued declines in fertility have various impacts on sexuality; put simply, the world will keep tilting toward one in which adult sexuality gains political traction at the expense to adult reproduction (child rearing).” (p. 305)
Put in evolutionary biological terms, more of an adult’s reproductive effort will be channeled to mating effort relative to parenting effort. That can mean less money spent on diapers and more on consumer products to advertise sexual allure. One could also argue that Las Vegas, where I reside and many of you have visited, already has grasped this changing fertility landscape. The city’s 1990s experiment to offer family-friendly themed casino experiences has largely been scrapped, with adult-oriented marketing (the hottest clubs with expensive bottle service) suggesting that it’s sex that sells best on the Strip.
Gray, P. B., and Garcia, J. R. (2013). Evolution and human sexual behavior. Cambridge: Harvard University Press.
Martin, R. (2013). How we do it: The evolution and future of human reproduction. New York: Basic Books.
Schmitt, D. P. et al. (2005). Sociosexuality from Argentina to Zimbabwe: A 48-nation study of sex, culture, and strategies of human mating. Behavioral and Brain Sciences 28, 247-311.
Wellings, K. and Johnson, A. M. (in press). Framing sexual health research: adopting a broader perspective. The Lancet.