A Fantastic Bonus 

I was stunned when my book, The Case of the Female Orgasm: Bias in the Science of Evolution, was attacked by feminists. I was called an “Uncle Tom for women”, and a columnist for the Guardian wrote that accepting the views of the book “would be a tragedy for women and risk returning to the sexual dark ages when so many thought sex was something men enjoyed and women endured.”

My book, which analyzes all twenty-one evolutionary accounts of female orgasm, admittedly does find only one explanation worthy of scientific merit. And that account is the one on which female orgasm is a “byproduct” of selection on the male orgasm, much as the male nipple is a byproduct of selection on female anatomy and the shared body plan and development in the womb. I’d expected the tongue-lashing that I received from some evolutionists unhappy with my critique of all the adaptive accounts—under which female orgasm is a special trait selected for its contribution to reproduction—but why the feminist dismay and fury?

I certainly erred in not renaming the “byproduct” account, which sex educator Susie Bright rightly noted makes female orgasm sound “like a can of Spam”. I now call it the “fantastic bonus” account, which is more like it. But there are several confusions in the uproar worth addressing.

Let’s start with the fact that it’s clear that evolution doesn’t dictate what’s culturally important. The capacities to read, write, play the violin, sing opera, and operate a computer are each enormously important traits in our culture—but they’re not evolutionary adaptations, they’re all byproducts. We—through our culture and society—decide what’s important, and that’s the way it should be.

But there is also something more for feminists to embrace in the book. Not only do I expose the male bias in many of the evolutionary accounts, but also the byproduct account opens a progressive vision of female sexuality. If female orgasm is not tied to reproductive function, then it enhances the century-long feminist effort to decouple female identity from female sexuality. The failure of many past evolutionary accounts is due to their lack of recognition of an autonomous female sexuality.

Eleven of the available twenty-one evolutionary explanations for female orgasm are based on the notion that a male-female pair bond is adaptive—that it contributes to getting more genes into future generations—and that female orgasm strengthens pair bonding. A pair bond is an attachment, usually monogamous, between a particular man and woman. The pair bond is supposed to be adaptive for several reasons, especially in that it helps with the raising of highly dependent human infants. The claim is that female orgasm provided the reliable reward for frequent intercourse, which helped “cement” the pair bond.

But there is a serious problem with this. In my survey of thirty-two studies spanning seventy-four years, I found that 20-25% of women reliably have orgasm with intercourse (either through unassisted or assisted intercourse, that is, by accompanying intercourse with direct stimulation of the clitoris by hand), while a full third of women never do; the rest of women sometimes do and sometimes don’t. This means that these evolutionary pair bond accounts that suppose women almost always have orgasm with intercourse have gone awry. Specifically, they seem to be assuming that women respond to intercourse the same way that men do—with orgasm. This is why I concluded that these accounts were “male-centered” or “male-biased”; they ignored what was already known about autonomous female sexuality and the infrequency with which women had orgasm with intercourse, and instead assumed that women had orgasm with intercourse on a regular basis. Oddly, some of these accounts actually cite the very sex studies that contain the evidence against them.

The most popular account nowadays of the evolution of female orgasm is the “sperm upsuck” account, which postulates that uterine suction occurs in the presence of a high quality male’s sperm. It is a form of mate selection, in which a high quality male’s sperm are more likely to fertilize the egg than those of a lower-quality male, through the sucking motion of the uterus (supposedly caused by female orgasm) moving the sperm through the reproductive tract.

This is a very old theory, dating back to the Greeks, but Robin Baker and Mark Bellis claimed to give new evidence for it in a pair of papers in 1993. Since then the sperm upsuck account has been very widely taught and accepted. But again, there are serious problems, the most glaring being with the statistics, in which some central findings are based largely on the results from a single subject—far too small a sample by scientific standards. In one table, for example, 93 of 127 data points come from one woman, while 4 of the other 10 couples contributed only 1 data point each. There are such grave problems with the statistics in their studies that their results fail to establish any of the conclusions claimed.

In sum, both the wide variability of female orgasmic response and the findings in the nonhuman primate world support the byproduct account. Stumptail macaque females wired to machines to record their muscle contractions exhibit all the physiological signs of orgasm, but they do so largely in the context of mounting other females, which would seem to defeat any reproductive account of female orgasm. And the very wide variability of human female orgasm—in which some women are very highly orgasmic, many women are “medium-orgasmic”, and 5-10% of women never have orgasm at all—is difficult to explain under any of the adaptive accounts so far given, but it is expected under the byproduct account, which predicts wide variability of the trait because it is not under selection.

This does not mean that female orgasm is not an adaptation—it may very well be! But scientific research to this date has not provided the evidence to establish this. The most promising adaptive accounts open for future research include those linking prolactin release, social rewards such as bonding, and female orgasm. Release of the neurotransmitter oxytocin, which has been linked to bonding as well in recent studies, might also have some promise, but it is complicated by the fact that oxytocin increases in orgasmic women vary so widely. Because the major increase in oxytocin levels occurs from touching, especially genital touching and intercourse, all before orgasm, and the actual increase from orgasm varies so widely, the real story on the adaptedness of oxytocin may lie in the earlier releases, and not in orgasm at all. But all of these avenues of research will hopefully be pursued, so that we can compare them against the byproduct account. Speaking of which, we return to the mystery of my solution to the feminist backlash…

Let’s review some history. The widely influential Freudian view said that female erotic pleasure is initially centered on the clitoris in infancy and childhood, but with the process of maturation into womanhood, the core of female eroticism must “migrate” to the vagina as the healthy woman’s “primary” erotic center. Women who failed to enact this migration—that is, women who remained dependent on the clitoris for orgasm or who failed to have orgasm from intercourse without additional clitoral stimulation—were “infantile,” “immature”, “neurotic”, “frigid”, or “dysfunctional”.

Masters and Johnson told us in 1965, by studying our basic biology and physiology, that women have only one basic source of orgasmic stimulation, the clitoris, and that Freud’s oppressive standard of the “vaginal” orgasm was a myth. Follow-up activism by feminists spread the pro-clitoris message far and wide. Thus, biology, sexology, and physiology provided the means to dismantle the devastating Freudian worldview on female orgasm. Biology became the ally of female orgasm.

But evolution wasn’t. Freud believed that all women ought to have orgasm from vaginal intercourse. But it is little known that this belief was explicitly derived from his conviction that female orgasm must be an evolutionary adaptation to promote reproduction. His adaptationism compelled him to assert that the adult woman would “complement” the man in reproductive sex. The big break away from this adaptationist and functional view kicked off the liberation of the female orgasm from its tragic constraints.

And now, some feminists fear that my views will be used to justify the neglect of orgasm. It seems that to them biology is now the enemy of female orgasm. After all, they see my biology as implying that orgasm is unimportant, or frivolous. Thus, it makes some sense that these feminists would be attacking me and my views. But this is based on a confusion of biological sciences in general with adaptationist theories of female orgasm.

But evolutionary adaptationists have continued to be the opponents of female satisfaction and autonomy. This is a major part of the discussion in my book. I reviewed the problem with the male-centered pair bond accounts, which ignored the realities of female sexual response, above. My analysis of these facts echoes the points made in the ’ 70s by sexologists and feminists against the adaptive Freudian views of female orgasm. Biology is still the ally of female orgasm, as we see, for example, in the new discovery of the large amount of hidden erectile tissue of the clitoris. And my biology, with its support of the open-ended, fantastic bonus view of the female orgasm, is an ally of female orgasm, too. But adaptationist evolutionary theory—with its coveted endowment of “usefulness”—isn’t, and never has been.

Elisabeth A. Lloyd is Arnold and Maxine Tanis Chair of History & Philosophy of Science and Professor of Biology at Indiana University, Bloomington. She is the author of The Case of the Female Orgasm: Bias in the Science of Evolution (Harvard University Press, 2005) and The Structure and Confirmation of Evolutionary Theory (Greenwood Press, 1988; Princeton University Press, 1994), as well as co-editor of Keywords in Evolutionary Biology (Harvard University Press, 1992) with Evelyn Fox Keller.