In this Egenis “Rapid Response” article, Professor John Dupre responds to recent reports showing that female sexual responsiveness could be genetic.
From London to Beijing, and across the globe, newspapers are buzzing with the latest news about female orgasm, published this week in the scientific journal Biology Letters. According to the headline in the London Times, ‘Secret of the female orgasm is shown to be a hereditary trait’. The article begins ‘The quality of a woman’s sex life depends largely on her genes, according to research that shows that her ability to have orgasms is as heritable as her blood pressure. The varying ease with which women reach sexual climax is more heavily influenced by genetic factors than any other, British scientists have found.’
The basis of this remarkable result is a large twin study that shows a significant heritability of the disposition of women to have orgasms during sex. Since this is taken to show that ease of having orgasms is a genetically caused trait it is also argued in various newspapers first, that this shows that the trait was evolved and, finally, that to have evolved it must have had some adaptive function.
The leader of the research team, Professor Tim Spector, of St Thomas’ Hospital in London, is quoted as speculating: “The theory goes that if a man is considered powerful enough, strong enough or thoughtful enough, in bed or in the cave, then he’s likely to hang around as a long-term partner and be a better bet for bringing up children. Women who orgasm too easily might be less good at selecting partners.”
This whole episode is paradigmatic of a certain kind of recurrent biological story, not least in the breadth of its uptake across the international media. It is therefore worth making a few elementary points about it.
First, establishing that a trait has a particular heritability has no bearing on the extent to which it is genetically caused. Heritabilities can change dramatically by changing background environmental factors, and for this reason no clear sense can be attached to the idea that a certain proportion of the causation of a trait is genetic.
On the other hand the claim that there are some genetic factors that affect the ability to have orgasms is entirely banal. Orgasm is a physiological response and human physiology has genetic causes. That differences in a physiological response are partly the result of genetic factors is hardly surprising. Unfortunately for men who might feel relieved to find that the shortcomings in their partners’ sexual experience was nothing to do with them, this is not something that could be established by this kind of research. The research confirms only what is already obvious, that as with most biological traits, many different kinds of factors are involved. A genuinely interesting question is whether women who do not achieve orgasms during sex (and wish to) are more likely to be helped by sexual education of them or their partners, or gene therapy or drugs targeting genetic errors. Given the likelihood that there is a large number of genetic loci potentially relevant to a complex physiological response of this kind, the prospects for the second strategy are likely to be very poor, contrary to a message perhaps suggested by the reports on this study.
Second, the quoted story about the possible adaptive response should be clearly identified as the sheerest speculation, and speculation that joins a longstanding and unfortunate history of such speculations. Female orgasm has been thought to be involved in reinforcing pair-bonding, or in encouraging the woman to lie on her back and reduce the risk of sperm loss, to take two examples. The fact that women tend to be less exhausted by orgasm than men, and therefore may be tempted to get right up and make the tea, illustrates the common androcentrism of many such speculations. Apart from the complete lack of evidence for any such theory, it should be observed that the argument that if something evolved it must be an adaptation is quite mistaken. Since we evolved, all our traits evolved. But not all are adaptations.
By far the most thorough and careful analysis of explanations of female orgasm is in a book recently published by Elisabeth Lloyd, The Case of the Female Orgasm: Bias in the Science of Evolution. Lloyd concludes tentatively that it is most probable that female orgasm isn’t an adaptation at all but, like male nipples, a consequence of developmental parallelisms between human males and females. The most important point is not to establish the correctness of this view, however, but to see this kind of evolutionary speculation as the science fiction that it is, and not necessarily harmless either. The notion of undiscriminating ‘women who orgasm too easily’ as evolutionary losers has some disturbing resonances with traditional fears of female sexuality, for instance.