The Case of the Female Orgasm : Bias in the Science of Evolution

by Elisabeth A. Lloyd

site: http://mypage.iu.edu/~ealloyd/


2005-05-19 / New York Times /

A critic takes on the logic of female orgasm

A plethora of different readings on the issue seen carrying a variety of implicit value judgments regarding the nature of woman

By Dinitia Smith


Evolutionary scientists have never had difficulty explaining the male orgasm, closely tied as it is to reproduction.

But the Darwinian logic behind the female orgasm has remained elusive. Women can have sexual intercourse and even become pregnant - doing their part for the perpetuation of the species - without experiencing orgasm. So what is its evolutionary purpose?

Over the last four decades, scientists have come up with a variety of theories, arguing, for example, that orgasm encourages women to have sex and, therefore, reproduce, or that it leads women to favor stronger and healthier men, maximizing their offspring's chances of survival.

But in a new book, Dr. Elisabeth A. Lloyd, a philosopher of science and professor of biology at Indiana University, takes on 20 leading theories and finds them wanting.

The female orgasm, she argues in the book, "The Case of the Female Orgasm: Bias in the Science of Evolution," has no evolutionary function at all.

Rather, Lloyd says the most convincing theory is one put forward in 1979 by Dr. Donald Symons, an anthropologist. That theory holds that female orgasms are simply artifacts - a byproduct of the parallel development of male and female embryos in the first eight or nine weeks of life.


In that early period, the nerve and tissue pathways are laid down for various reflexes, including the orgasm, Lloyd said. As development progresses, male hormones saturate the embryo, and sexuality is defined.

In boys, the penis develops, along with the potential to have orgasms and ejaculate, while "females get the nerve pathways for orgasm by initially having the same body plan."

Nipples in men are similarly vestigial, Lloyd pointed out. While nipples in woman serve a purpose, male nipples appear to be simply left over from the initial stage of embryonic development.

The female orgasm, she said, "is for fun."

Lloyd said scientists had insisted on finding an evolutionary function for female orgasm in humans either because they were invested in believing that women's sexuality must exactly parallel that of men or because they were convinced that all traits had to be "adaptations," that is, serve an evolutionary function.

Expectations that normalize

Theories of female orgasm are significant, she added, because "men's expectations about women's normal sexuality, about how women should perform, are built around these notions."

"And men are the ones who reflect back immediately to the woman whether or not she is adequate sexually," Lloyd continued.

Central to her thesis is the question of how often women experience orgasms during sexual intercourse.

She analyzed 32 studies, conducted over 74 years, of the frequency of female orgasm during intercourse.

When intercourse was "unassisted," that is not accompanied by stimulation of the clitoris, just a quarter of the women studied experienced orgasms often or very often during intercourse, she found.

Five percent to 10 percent never had orgasms.

Yet many of the women became pregnant.

Lloyd's figures are lower than those offered by Dr. Alfred A. Kinsey in his 1953 book, "Sexual Behavior in the Human Female." Kinsey's studies found that 39 percent to 47 percent of women reported that they always, or almost always, had orgasm during intercourse.

But Kinsey, Lloyd said, included orgasms assisted by clitoral stimulation.

Lloyd said there was no doubt in her mind that the clitoris was an evolutionary adaptation, selected to create excitement, leading to sexual intercourse and then reproduction.

But, "without a link to fertility or reproduction," Lloyd said, "orgasm cannot be an adaptation."

Not everyone agrees. For example, Dr. John Alcock, a professor of biology at Arizona State University, criticized an earlier version of Lloyd's thesis, presented in 1987, when it appeared in an article by Stephen Jay Gould in the magazine Natural History.

In a phone interview, Alcock said that he had not read her new book, but that he still maintained the hypothesis that the fact that "orgasm doesn't occur every time a woman has intercourse is not evidence that it's not adaptive."

"I'm flabbergasted by the notion that orgasm has to happen every time to be adaptive," he added.

Assessing quality

Alcock theorized that a woman might use orgasm "as an unconscious way to evaluate the quality of the male," his genetic fitness and, thus, how suitable he would be as a father for her offspring.

"Under those circumstances, you wouldn't expect her to have it every time," Alcock said.

Among the theories that Lloyd addresses in her book is one proposed in 1993, by Dr. R. Robin Baker and Dr. Mark A. Bellis, at Manchester University in England. In two papers published in the journal Animal Behaviour, they argued that female orgasm was a way of manipulating the retention of sperm by creating suction in the uterus. When a woman has an orgasm from one minute before the man ejaculates to 45 minutes after, she retains more sperm, they said.

Furthermore, they asserted, when a woman has intercourse with a man other than her regular sexual partner, she is more likely to have an orgasm in that prime time span and thus retain more sperm, presumably making conception more likely. They postulated that women seek other partners in an effort to obtain better genes for their offspring.

Lloyd said the Baker-Bellis argument was "fatally flawed because their sample size is too small."

"In one table," she said, "73 percent of the data is based on the experience of one person."

In an e-mail message recently, Baker wrote that his and Bellis' manuscript had "received intense peer review appraisal" before publication. Statisticians were among the reviewers, he said, and they noted that some sample sizes were small, "but considered that none of these were fatal to our paper."

Lloyd said that studies called into question the logic of such theories. Research by Dr. Ludwig Wildt and his colleagues at the University of Erlangen-Nuremberg in Germany in 1998, for example, found that in a healthy woman the uterus undergoes peristaltic contractions throughout the day in the absence of sexual intercourse or orgasm. This casts doubt, Lloyd argues, on the idea that the contractions of orgasm somehow affect sperm retention.

Another hypothesis, proposed in 1995 by Dr. Randy Thornhill, a professor of biology at the University of New Mexico and two colleagues, held that women were more likely to have orgasms during intercourse with men with symmetrical physical features. On the basis of earlier studies of physical attraction, Thornhill argued that symmetry might be an indicator of genetic fitness.

Lloyd, however, said those conclusions were not viable because "they only cover a minority of women, 45 percent, who say they sometimes do, and sometimes don't, have orgasm during intercourse."

"It excludes women on either end of the spectrum," she said. "The 25 percent who say they almost always have orgasm in intercourse and the 30 percent who say they rarely or never do. And that last 30 percent includes the 10 percent who say they never have orgasm under any circumstances."

In a phone interview, Thornhill said that he had not read Lloyd's book but that the fact that not all women have orgasms during intercourse supports his theory.

"There will be patterns in orgasm with preferred and not preferred men," he said.

Lloyd also criticized work by Sarah Blaffer Hrdy, an emeritus professor of anthropology at the University of California, Davis, who studies primate behavior and female reproductive strategies.

Scientists have documented that orgasm occurs in some female primates; for other mammals, whether orgasm occurs remains an open question.

In the 1981 book "The Woman That Never Evolved" and in her other work, Hrdy, argues that orgasm evolved in nonhuman primates as a way for the female to protect her offspring from the depredation of males.

Looking at the primates

She points out that langur monkeys have a high infant mortality rate, with 30 percent of deaths a result of babies' being killed by males who are not the fathers. Male langurs, she says, will not kill the babies of females they have mated with.

In macaques and chimpanzees, she said, females are conditioned by the pleasurable sensations of clitoral stimulation to keep copulating with multiple partners until they have an orgasm. Thus, males do not know which infants are theirs and which are not and do not attack them.

Hrdy also argues against the idea that female orgasm is an artifact of the early parallel development of male and female embryos.

"I'm convinced," she said, "that the selection of the clitoris is quite separate from that of the penis in males."

In critiquing Hrdy's view, Lloyd disputes the idea that longer periods of sexual intercourse lead to a higher incidence of orgasm, something that if it is true, may provide an evolutionary rationale for female orgasm.

But Hrdy said her work did not speak one way or another to the issue of female orgasm in humans. "My hypothesis is silent," she said.

One possibility, Hrdy said, is that orgasm in women may have been an adaptive trait in our prehuman ancestors.

"But we separated from our common primate ancestors about 7 million years ago," she said.

"Perhaps the reason orgasm is so erratic is that it's phasing out," Hrdy said. "Our descendants on the starships may well wonder what all the fuss was about."

Western culture is suffused with images of women's sexuality, of women in the throes of orgasm during intercourse and seeming to reach heights of pleasure that are rare, if not impossible, for most women in everyday life.

"Accounts of our evolutionary past tell us how the various parts of our body should function," Lloyd said.

If women, she said, are told that it is "natural" to have orgasms every time they have intercourse and that orgasms will help make them pregnant, then they feel inadequate or inferior or abnormal when they do not achieve it.

"Getting the evolutionary story straight has potentially very large social and personal consequences for all women," Lloyd said. "And indirectly for men, as well."



Friday, May 27, 2005

Female Orgasm: Proof Of God
Science can't explain it, evolution can't understand it and men can only lie there in awe

By Mark Morford, SF Gate Columnist

Women have orgasms because they can. Women have orgasms because it's the right thing to do.

Women have orgasms because by and large they refuse to launch monstrous ultraviolent illegal soul-deadening wars over oilsucking phallocentric powermad landwhoring BS powergrabs and therefore they fully deserve all the inexplicable otherworldly cosmically infused clitorally energized pleasures they can get.

Did you catch that keyword? That note of strangeness? It was right there, in the word inexplicable. Because apparently, as far as science is concerned and despite the obvious reasons I assert above, no one really seems to know exactly why women have orgasms at all.

Observe, won't you, a new book by a soft-spoken scientist named Dr. Elisabeth Lloyd, from Indiana U, that basically claims there is no justifiable evolutionary need for the female orgasm whatsoever, that it really serves no known biological purpose and that it's becoming, therefore, increasingly obsolete and redundant and more or less unnecessary.

Note how much fun Dr. Lloyd must be at parties. Or on a date.

After all, the book concludes, the clitoris merely exists to create excitement to promote reproduction, but the female orgasm is merely a weird biological afterthought, a remembrance of things past, a wisp of a hint of something that came long before that maybe only our ape ancestors could fully appreciate and make good use of, mostly for generating a more potent, primitive urge to make little furry ape babies.

But now witness, argues the book, the heartbreaking number of modern non-ape women who have tragically low or nonexistent sex drives but who still feel absolutely compelled to pop out a nice brood of offspring. The female orgasm, clearly, ain't for procreation. It has no effect on the transport of sperm. It doesn't drive maternal desire. So, if the urge to orgasm has no connection with the urge to procreate, why do women get them at all?

This is the great thing about science. It gets all flabbergasted and confounded and scrunchy when confronted with things it doesn't quite understand and that it can't quite figure out and that don't fit into neat categories, especially if said things are astounding explosive events that make women moan and writhe and gasp and grin and feel their deep inborn prelapsarian connection to just about all of eternity, in the space of about 17 seconds.

There is no room in this mode of science for, you know, mystery. There is no room for the deeply funky or the hotly mystical, the moist divine wild card. This is because stiff little science tends to cram all possibility for a given explanation into the great maw of cold beautiful logic and spits out, sadly and tellingly and almost without fail, the cosmic hunks of mystical possibility as if they were indigestible bones.

That scientific view is, of course, one way to look at it. There is, naturally, another.

Let us open up a little, go deep and explore and probe further and say, ahh yes. Because it can also be very easily argued that the female orgasm is, quite simply, the Great Mystical Link, the hot divine thing that connects and communicates and interrelates between heaven and Earth, mind and body, soul and sky, dream state and anal bead, Astroglide and God.

Maybe, in other words, the female orgasm doesn't need a purely biological purpose. Maybe it's about something more. Maybe it has -- dare we say it? -- a spiritual purpose. Vibrational. Transcendental. Gasp! Hide the children.

Well, why not? Have you seen a wild female orgasm lately? Have you borne witness? Because you really, really should. One good look and the fact comes clear: The thing is at once directly hardwired to the deep chthonic Earth while at the same time has the bright shimmering cosmos on speed dial. It's true. It's obvious. Any good and deeply felt female climax is clearly a subatomic vibrational pulse of such unusual and kaleidoscopic frequency that the only ones who can truly hear its messages are purple orchids and bright red snakes and the aliens who built the Great Pyramids. All hail.

So then. If you want to argue that anything has been lost to the mists of time and awareness, let's argue that. Let's lament the demise of that link, the great orgasmic disconnect, the massive cultural spin downward toward sexual terror and orgasmic stagnation and Laura Bush.

In other words, let's argue that the female orgasm, far from becoming obsolete and useless, is more necessary and vital than ever before, because it is the orgasm that allows us a glimpse of what lies beyond, of what we can become, of all that there is and all we want to be and all we want to become and it's all wrapped up in a white-hot moment of transcendental moaning hope. Plus, as I understand it, they're just tremendous amounts of fun.

So now, if Lloyd's book is to be believed, the fact that women are losing the orgasmic impulse, the fact that the female water slide is not worshipped and studied and taught like a joyful religion or glorious deity in this dazed and confused and Bush-ravaged culture, and the sad fact that every girl is not given a new Hitachi Magic Wand as a beautiful rite of passage when she hits 14, these are more than merely the great tragedies of our age. They might very well be the things keeping us from progressing at all.

Which is to say, deny the power of the mystico-erotic spiritual gasp at your peril. Look to science to explain away all our slick needful quiverings as mere rote mechanical factions, and watch the spirit wither and cringe and say uh, hello, over here, please, what the hell is wrong with you people?

The female orgasm is just useless fun? Just a vestigial remnant of our licentious monkey ancestors, increasingly obsolete and something that will soon be completely replaced with lots of yawning and sighing and a slow steady gaze at the ceiling as she ponders paint colors for the kitchen while the man sweats and grunts and enjoys 2.3 minutes of primitive emasculated gorilla lust? Hardly. Leave that for the Republicans and the Christian Right.

Woman's orgasm has no evolutionary purpose? Bull. Woman's orgasm is proof of evolution, baby. Spiritual, karmic, celestial evolution. It is what propels us forward, brings us light and awareness and deep laughing cosmic moan and makes much of life worth living. And if we lose our grip on that notion and insist on devolving at our current rate, we will be in deep trouble indeed.

Magic Wands all around, Dr. Lloyd. It's the right thing to do.

Mark Morford's Notes & Errata column appears every Wednesday and Friday on SF Gate, unless it appears on Tuesdays and Thursdays, which it never does.


April 24, 2005


Orgasmic science

By Christopher Shea  

THE LATE Stephen Jay Gould was quite fond of his nipples. As the Harvard paleontologist wrote in a 1987 essay in the magazine Natural History, the fact that male nipples, as virtually all biologists believe, are a mere developmental echo of female nipples - whose purpose in child-rearing is obvious - is no reason to think less of them. ''I, for one, am quite attached to all my body parts,'' he wrote, no matter how useless they may seem.

Gould made that argument as an entrée into a touchier one: He went on to suggest that the clitoris, and by extension the female orgasm, also had no purpose in evolutionary terms. In a situation exactly analogous to the male nipple, Gould wrote, the clitoris and the female orgasm were simply developmental echoes of the male penis and orgasm, whose importance to reproduction is obvious.

Gould's article (later reprinted under the title ''Male Nipples and Clitoral Ripples'') ignited a war in the letters column of Natural History, though he was not the first to make the argument that the female orgasm serves no evolutionary purpose. After the anthropologist Donald Symons made the same point in his 1979 book ''The Evolution of Human Sexuality,'' the feminist anthropologist Sarah Blaffer Hrdy noted in a review that ''a gentlemanly breeze from the 19th century drifts from the pages.'' The argument that the male orgasm was a naturally selected miracle and the female one a wan copy, she thought, smacked of sexism.

In his essay, Gould said he had been influenced by the writings of a young philosopher of science named Elisabeth A. Lloyd. Now Lloyd, a professor at Indiana University, is coming forward with a full-blown book that brings his argument up to date.

In ''The Case of the Female Orgasm: Bias in the Science of Evolution,'' published next month by Harvard University Press, Lloyd summarizes dozens of evolutionary accounts of the female orgasm - and knocks them all down. Like Gould, she thinks the female orgasm is purposeless, which is not to say pleasureless. And she extends the charge of bias, charging that too many scientists take the male-centered view that the female orgasm is closely linked to heterosexual intercourse and reproduction. ''The history of evolutionary explanations of female orgasm,'' Lloyd writes, ''is a history of missteps, misuse of evidence, and missed references.''

. . .

Until the 1970s or so, it was thought that women were the only female primates to experience orgasm, which led some scientists to speculate that in humans the female orgasm served as a sort of replacement for estrus, or ''heat'' - an encouragement to mate. But sightings of give-away shrieks and grimaces among female primates - which tended, incidentally, to occur more frequently in same-sex encounters - chipped away at this conventional wisdom.

Even in humans, male-female coitus is an iffy route to female orgasm, Lloyd notes in her book. (She declined to be interviewed for this article.) According to research she cites, only 55 percent of women have orgasms more than half the time during intercourse, while 5 to 10 percent never have them under any circumstances.

The ''tremendous variation in the manifestation of the female orgasm,'' says Richard Wrangham, a professor of anthropology at Harvard, ''doesn't seem compatible with an evolutionary history in which it is enormously important.''

But this hasn't stopped other researchers from speculating on the female orgasm's role in natural selection. In his 1967 pop-science classic ''The Naked Ape,'' the Oxford-trained zoologist Desmond Morris argued that the female orgasm evolved to cement the male-female pair bond, which gave offspring a survival advantage. Furthermore, Morris wrote, when it comes to fertilization ''there is a great advantage in any reaction that tends to keep the female horizontal when the male ejaculates and stops copulation.''

Lloyd wryly points out a couple of problems here. First, connection between the female pursuit of orgasms and monogamy is not exactly self-evident. Second, the link between a ''horizontal'' position and the female orgasm is also less than ironclad.

Lloyd likewise dismisses the explicitly feminist theories of Sarah Blaffer Hrdy, professor emeritus of anthropology at the University of California at Davis. Hrdy, who been tinkering with her theories since the late 1970s, believes that the female orgasm evolved to encourage females to mate with numerous men in pursuit of those elusive fireworks. The evolutionary benefits of multiple partners? Not only would women be more likely to conceive, but men would be less likely to kill the resulting infants, since no one would be sure whose child was whose.

According to Lloyd, Hrdy too succumbs to the fallacy that orgasm has a strong link to procreative intercourse, especially given how little attention our ancestor males probably gave to the clitoris (other primate males ignore it). Hrdy counters via email that an alleged emphasis on penetration in the theory ''is [Lloyd's] insertion (no pun intended), not my assumption.'' The theory would still hold if females supplemented coitus with self-stimulation and other sex play, she contends.

Throughout the 1990s, researchers continued to look for empirical evidence that the female orgasm contributed to reproductive success. In 1993, writing in the journal Animal Behaviour, Robin Baker and Mark Bellis reported confirmation of the indelicately named ''upsuck'' theory. After measuring (self-collected) semen that flowed out of the vaginas of 32 women following intercourse, Baker and Bellis concluded that orgasms from one minute before male climax to 45 minutes afterwards increased the amount of semen retained by the female.

In 1995, in the same journal, Randy Thornhill, a biologist at the University of New Mexico, and two colleagues announced that female frequency of orgasm correlated with the physical ''symmetry'' of their partners' bodies, which in many species is a rough proxy for health and reproductive fitness. This finding, they claimed, suggested that the orgasm helped steer women toward mates more likely to produce healthy offspring.

Lloyd sees desperation in the sheer variety of proposed explanations for the orgasm. (She also sees fatal statistical problems in the Baker and Bellis article, which Baker, in an email, disputes.) Meanwhile, her critics see her drive to shoot down all adaptive arguments as quixotic.

''If the clitoris is an irrelevant organ,'' asks the Emory University psychologist and primatologist Frans de Waal, ''why in cultures that want to control female sexuality do they have it removed?''

But wherever the argument goes, most female onlookers are likely to view their orgasms as the late Professor Gould viewed his nipples. Purpose, shmurpose. I'm just going to enjoy them.

Christopher Shea's column appears in Ideas biweekly.





O my!


Saturday, May 28, 2005 Page D10

O: The Intimate History of the Orgasm

By Jonathan Margolis

The Case of the Female Orgasm

Bias in the Science of Evolution
by Elisabeth A. Lloyd
Harvard University Press, 2005

The orgasm," writes Jonathan Margolis in his delightful, wide-ranging history on the subject, "is the ultimate point of . . . sex. It is what we hope to attain. As any football fan will confirm, there is enjoyment to be had from a game that ends in a nil-nil scoreline, but a great match requires goals. And many of the greatest matches, for connoisseurs, have been high-scoring draws, with equal satisfaction on both sides."

Like many of us, Margolis takes it for granted that, for both men and women, climax is simply meant to accompany sex, and that there must be some good evolutionary reason for it. In other words, there must be genetic influences on orgasm, and people who happened to have had those orgasm genes and were good at it, fared better in the reproductive stakes. Figuring out how that might have worked for men is simple: Orgasm rewards them for spreading their seed. But what about women?

There are several intriguing suggestions. One is that keeping women sexually satisfied helps keep couples, or "pair-bonds," together. In the days when men went off hunting for weeks at a time, the argument goes, they needed to be confident that their women back at the camp were going to stay true, and being great in bed was one way of increasing the odds of that. Another idea is that orgasm signals female satisfaction and therefore fidelity, so it helps protect her from male jealousy.

Other theories propose that orgasm during intercourse actually increases a woman's chance of getting pregnant. Various accounts are put forward: In one, it's because female orgasm promotes male orgasm and ejaculation; in another, it's because orgasm relieves the "vasocongestion" that can allegedly interfere with fertility; in yet another, orgasm creates an "upsuck" that physically pulls sperm further into the reproductive tract, where it's more likely to bump into an egg. By extension, the guy who can give a gal the bigger thrill may be more likely to father her child -- even if several studs are competing during the same cycle.

Margolis has great fun with all of this. In his chapter titled The Evolutionary Paradox of Orgasm, he gives a concise, if largely unreferenced, overview of the disparate views, and what they might mean. He peppers his prose liberally with clever little nuggets like this one: "There is a broad, cross-cultural, popular perception, accurate or not, that women set out with a generalized longing for romance, affection and security that only finds proper fulfilment with the relief of a localized neural desire in the pelvic region; whereas men set out with a localized neural desire in the pelvic region that only finds proper fulfilment in romance, affection and security."

For Margolis, a British writer and journalist, why female orgasm exists is just another curiosity in a book that trades on such curiosities (how the clitoris was "discovered" at least twice, for instance, or that even piano legs had to be draped in crinolines at the height of American prudery).

Enter Elisabeth Lloyd. She is a philosopher of science at Indiana University, and female orgasm is the meat and potatoes of her book. In it, she examines all 20 published theories about why female orgasm exists, and she declares all but one seriously flawed. Phrases like "grossly deficient evidence" and "highly misleading" are common fare here, and not even the most prominent researchers in the field escape her censure.

Two books could hardly be more different. Whereas Margolis is playful and light and dances merrily along the surface, Lloyd is serious and scholarly and digs deep. His writing could be described as flirtatious, and hers as, well, frigid. But while his book is by far the more entertaining, hers is the more rewarding. His book leaves you vaguely suspicious that a crucial shoebox was left unopened under the unmade bed, but with hers, you know even the dust bunnies have been analyzed under the microscope. Lloyd not only cites extensively, she also points out where the original authors drew the wrong conclusions about their own data. She is the Sheila Fraser of science, and she's holding a public inquiry.

Let's just take the idea of "upsuck," for instance. Several highly regarded theories rest on the idea that orgasm somehow assists sperm in getting where it needs to go. But is there evidence for this? One research team in 1970 claimed to show that there was a drop in uterine pressure following orgasm, which they believed would create such a sucking action, and this paper is widely cited as persuasive evidence for upsuck. But as Lloyd points out, those researchers only studied one female subject during a grand total of two episodes of sex. And, critically, they did not test whether semen moved one way or the other. Other researchers who did try to measure such movement did not find it.

Or take intercourse itself. According to people who study sex, such as Masters and Johnson, female orgasm during intercourse isn't as common as we like to presume. About half of all women routinely do not reach orgasm when they have intercourse, and a small percentage simply never do. Many researchers choose simply to overlook this. "What is most peculiar about these authors," writes Lloyd, "is their ritual citation of the sex literature, despite the fact that the very results cited show exactly the discrepancy they ignore."

On the other hand, almost all women are able to reach orgasm by other means. This is odd. It suggests that, for women, orgasm may not have much to do with intercourse at all, and by association, with reproduction. Observations of some of our primate relatives seem to bear this out. A study of stumptail macaques, one of only a few studies of female orgasm outside the human family, revealed that when females had orgasms, it was always with other females -- never, apparently with males -- and that these orgasms did not take place during the fertile period.

Despite never witnessing heterosexual orgasms in these female monkeys, the researcher who did the stumptail work assumed that if orgasm happened between females, it must happen between males and females, too. Ironically, these findings became "strong evidence" for the existence in the stumptails of orgasm during copulation. Says Lloyd: "I suggest that [the researcher] is committed to showing that females get the same pleasure out of sexual intercourse that males do, regardless of her evidence."

Leaving no stone unturned, and finding a good deal of rot underneath them all, Lloyd concludes that there is no evidence linking female orgasm to increased fertility. There is no convincing evidence, she says, that female orgasm is an adaptation at all. The only theory that fits with the available evidence is the idea that female orgasm is a bit of an accident -- a mere byproduct of the male need for it.

That proposal, largely ignored, was first put forward in 1979 by Donald Symons, who remarked that "human female orgasm is best regarded as a potential." During the first seven or so weeks in utero, before hormones start to differentiate us, males and females are essentially the same template. Importantly, the penis and the clitoris are the same structure -- set on different developmental paths only by the bath of hormones they receive starting in week eight of gestation. In that sense, females only have a clitoris, and therefore the means to experience orgasm, because males need a penis -- in exactly the same way males have nipples because females need to be able to nurse their young.

Okay, I admit it, Lloyd's book is penetrating and tantalizing, even intensely satisfying, but her conclusion about how female orgasm may have come about is a bit of an anticlimax. A byproduct? Hmph. But her findings about the scientific process really are something to scream about.

Alison Motluk is a science journalist based in Toronto.


The Study of O
The female orgasm as evolution's happy accident.

By Amanda Schaffer

Posted Thursday, May 26, 2005, at 4:19 AM PT


Elisabeth Lloyd, a soft-spoken philosopher of biology, didn't expect to serve up jokes on Saturday Night Live when she published an academic book late last month. But The Case of the Female Orgasm hit a cultural G spot. After the New York Times featured Lloyd in last Tuesday's science section, her phone started ringing, and by Thursday she was chatting about orgasms with Barbara Walters and the other women on ABC's The View. Saturday Night Live parodied the book as a "case of" mystery that's "a real departure for The Hardy Boys."

Why the fuss? Lloyd's central claim is not new. But her study of evolution and orgasm offers the most thorough and serious treatment of the subject to date—and strongly rejects the claim that orgasm in women serves an evolutionary purpose. Lloyd has scrutinized 21 evolutionary accounts of female orgasm and makes a convincing case for the single account that treats orgasm as a happy accident, a byproduct of the role that male orgasm plays in reproduction and the sharing of early embryonic tissue by the male and female genitalia. The other 20 theories she dismisses as illogical or incompatible with data on women's sexuality. This time the press has it right. Lloyd's analysis is worth all the attention. She hasn't definitively settled the debate: One new line of inquiry could pose a challenge to her thesis. But it probably wouldn't be a fatal one, so score one for the orgasm as pure pleasure.

That approach was first advanced in 1979 by anthropologist Donald Symons. He argued that orgasm is possible in women because it is crucial in men. Embryos of both sexes have a common body plan early on, so when male orgasm is selected for by evolution, female orgasm comes along for the ride. Symons' explanation, dubbed the "byproduct account," was never popular among biologists. Most believed that female orgasm must somehow contribute directly to women's reproductive success (in evolutionary terms, must be an adaptation). Nor did the work go over well with feminists, who thought it cast women's sexual experience as derivative of men's.

When Lloyd began to investigate the science of orgasm in 1984, she was impressed by Symons' work. She mentioned it to Stephen Jay Gould in 1986, while they were collaborating on a paper about species selection. Gould was intrigued and said he'd like to write up the byproduct account for his column in Natural History. Lloyd shored up her documentation and handed Gould a 50-page, single-spaced manuscript—the seed that would eventually grow into her current book. When Gould's column "Freudian Slip" appeared in the February 1987 issue of Natural History, it set off an academic firestorm, provoking particularly aggressive attacks from John Alcock, a fervent proponent of adaptive explanation. It was Gould, not Lloyd, who was called on to defend the byproduct stance; Lloyd says that she did not then want the intense attention.

In the 1990s, Symons' theory largely receded from the spotlight. A new mini-genre of adaptive explanations that assume a link between female orgasm and reproductive success came to the fore. These "sperm competition" theories suggest that female orgasm somehow helps to draw sperm up through the cervix and uterus, thus aiding fertilization and reproduction. Many sociobiologists and scientists who study animal behavior now take sperm competition virtually for granted. According to Lloyd, fertility specialists sometimes tell women to lie on their backs and masturbate to orgasm after being artificially inseminated.

Lloyd dismisses the 20 theories of orgasm that assume an evolutionary purpose for female orgasm mainly because they overlook data on women's sexuality or make untenable leaps of logic. One well-known argument first advanced by zoologist Desmond Morris in 1967, for instance, claims that orgasm tires out women and causes them to lie immobile, on their backs, increasing the chances of fertilization by preventing sperm from leaking out. But as Lloyd notes, it is men, more than women, who tend to be sated and exhausted after orgasm. And women are more likely to reach orgasm when they're on top of their partners, in which case gravity doesn't work in favor of fertilization. Even when women climax lying on their backs, multiple studies have found no discernible upward flow of sperm—one experiment (by the sex researchers Masters and Johnson) seems to suggest that sperm is actually expelled from the uterus by orgasmic contractions. Throughout the book, Lloyd pinpoints the flaws in the theories with which she disagrees and emphasizes that there are no data correlating female orgasm with any aspect of fertility or reproductive success.

Lloyd endorses the alternate theory that orgasm is a byproduct because it meshes easily with the findings of sex research. Women tend to reach orgasm more quickly through masturbation than through heterosexual sex, for example, and when most masturbate, they don't mimic the act of penetration. And then of course there are all the women who don't reach orgasm through intercourse at all. All of this make far more sense if women's potential for orgasm is understood as separate from their potential for childbearing. Lloyd even gives the byproduct theory a new and appealing feminist twist: By not equating the pleasure of orgasm with the ability to have kids, she argues, it is more ur-woman than its competitors.

Lloyd's work has so far generated a few thoughtful responses and a host of misconceptions. (Read some of the ones rippling through the blogosphere, along with responses to them.) Where will the debate go next? Lloyd has successfully rebutted most of the key findings on which the orgasm-is-adaptive arguments currently depend. But research involving the hormone oxytocin could bolster the case that orgasm serves an evolutionary purpose and prompt a new round of wrangling. Oxytocin is best-known for the role it plays in spurring lactation and some of the contractions associated with labor. In a recent experiment, the uteri of women injected with oxytocin tended to draw in fluid (think sperm), suggesting a possible mechanism for enhanced fertility. Orgasm is associated with oxytocin release. But so is any kind of vaginal or cervical stimulation. In other words, it could be sex, and not orgasm, that is causing the oxytocin release that increases a woman's chances of getting pregnant. Which would be no help to the adaptationist camp after all.

To really boost their argument, adaptationists would need to show that substantially higher levels of oxytocin are consistently released with female orgasm; that this release is associated with a large increase of fluid movement through the reproductive tract; and that female orgasm is correlated with higher fertility rates and more babies. Even if strong data along those lines appear, the primary explanation for female orgasm could still be Symons' and Lloyd's—the common embryological origins of male and female genitalia. That is, small changes in either the clitoris or the nervous pathways associated with orgasm, which could have made orgasm more intense or easier to achieve, may be favored by some as-yet-undocumented selection pressure. But that adaptation could have nothing to do with the origins of female climax. Orgasm in women could still be first and foremost an offshoot of orgasm in men. In short, the burden of proof now lies with Lloyd's opponents.


Amanda Schaffer is a frequent contributor to Slate.



The Case of the Female Orgasm

Bias in the Science of Evolution
by Elisabeth A. Lloyd
Harvard University Press, 2005

Review by Rob Loftis, Ph.D. on Aug 2nd 2005


Elizabeth Lloyd's new book has attracted a lot of attention for a technical work of academic philosophy, including profiles in the New York Times and Slate, and an appearance on The View (right between an interview with television doctor Noah Wyle about the health insurance crisis in America and a tribute to Merv Griffin). Lloyd was even the subject of a joke on Saturday Night Live's "Weekend Update," certainly a first for the philosophic community. 

Lloyd's book is obviously receiving attention because her topic is, quite literally, sexy. But perhaps more importantly for the popular media, her theses are very easy to state in layman's terms. Lloyd believes that the female orgasm is a evolutionary byproduct of the male orgasm, the same way that male nipples are a byproduct of the evolution of female nipples. Furthermore, she believes that biases in the research community have prevented scientists from seeing this obvious truth, including a bias toward adaptive explanations and a nasty tendency to assume female sexuality is like male sexuality. Clearly, she has an interesting and important set of theses. On top of that, her argument has a straightforward, logical structure. She canvasses the 20 adaptive accounts that have been proposed so far and finds obvious gaps in reasoning, while the one nonadaptive account has a lot of prima facie evidence for it. It is nice to see that you can get on television with a clear and important argument.

Once you get into the details of her refutations of the individual adaptive accounts things become more complicated, but certain consistent themes emerge. Twelve of the accounts she surveys are pair-bond accounts that is, they assert that the female orgasm evolved to reinforce a monogamous bond between a man and a woman. All of these accounts descend, in one way or another, from Desmond Morris's infamous The Naked Ape, which painted a popular, seductive picture of human evolution that was little more than a projection of his contemporary Father Knows Best suburban culture on our hominid ancestors. All of the pair-bond accounts falter on a basic fact of female sexuality. Women do not orgasm reliably with vaginal intercourse. After a painstaking review of the sexology literature since 1921, Lloyd concludes that about 10% of women never have orgasm with vaginal intercourse and about 25% always have orgasm with intercourse. The middle 65% of women are contingent orgasmers, climaxing when the circumstances are right. In contrast, 95% of women who masturbate can achieve orgasm that way, and they do so in the same amount of time it takes men to orgasm, about four minutes. None of the pair-bond accounts can explain this distribution. For Morris, the orgasm simply reinforced the pair bond. But if that were the case, we would expect selective pressure towards consistent orgasm. So 75% of the variation is left unexplained. A more sophisticated pair-bond account, due to John Alcock, suggests that female orgasm serves a function in mate selection: men with the decency to give their partners orgasm are also likely to be good fathers, so contingent orgasmers have an advantage over others in their ability to select good mates. But this account still leaves 35% of the variation--the women who always or never orgasm--unexplained.

Other adaptive accounts run into other problems. Many are based on faulty work by Baker and Bellis which purported to show that orgasm causes an "upsuck" of sperm into the uterus. At the most basic level, there is no empirical evidence that women who orgasm have had more reproductive success than women who do not. In the end, Lloyd argues that the loyalty to adaptive explanations can only come from an irrational bias toward adaptive explanations and a failure to understand female sexuality, evidenced primarily in the failure to appreciate the variation in female ability to orgasm.

The structure of Lloyd's argument suggests an easy route for rebuttal: one simply goes looking for missing adaptationist accounts. The book would be obviously inadequate if there were compelling accounts out there that were overlooked. This line of argument turns up some oddities. No account that has actually been developed in the literature Lloyd is critiquing has been overlooked, so her charge of bias holds up. However, there are nascent ideas in the literature that Lloyd does not hit on, some of which may yield fruit in the future. One popular account of the male orgasm is the "when to stop masturbating theory." It is obviously adaptive for men to enjoy stimulating their genitals, but without a clue as to when to stop men could actually damage their sex organs from too much rubbing. Male orgasm, on this theory, lets us spare our chafed privates and move on to other things. Why not extend this account to women? The female version of this theory is missing from Lloyd's book, but that is no loss because the female version of the theory is a nonstarter. It only works if you assume that female orgasm is like male orgasm in that it makes one sleepy and uninterested in sex. But Masters and Johnson, along with personal experience and popular wisdom, show that this is not the case. Women, after orgasm, return to a plateau level of sexual excitement.

More troubling is the absence of serious discussion of possible models for the evolution of human sexuality from the bonobo research. Right now we have a fairly clear picture of bonobo sexuality, both from field studies like the work of Takyoshi Kano and Hohmann and Fruth and from captivity studies like the work of Franz de Waal. These studies show that bonobos use sex to mediate a wide range of social difficulties, including preventing conflicts and aiding reconciliation after conflicts, regulating tension, solidifying same-sex and different-sex alliances, and expressing social status. A parallel account of the evolution of the human female orgasm would be a kind of social bonding account, quite distinct from the pair-bond accounts offered by Morris and his followers. Such an account would not stumble on what Lloyd calls the orgasm/intercourse discrepancy, because stimulation would not be limited to vaginal penetration, but could include cunnilingus and manual stimulation.

In an email to me, Lloyd said she was open to such an account, but has her doubts, largely because the cross-cultural evidence suggests that males typically show little interest in providing direct clitoral stimulation, or in female pleasure at all, and because competition between females played more of a role in human evolution than cooperation, at least according to Sarah Hardy. In any case, this account has never been fully developed, so Lloyd does not need to respond to it. It does, however, reveal an oddity in Lloyd's argument. For Lloyd, the so called "orgasm/intercourse discrepancy" is a crucial piece of evidence revealing androcentric bias in current research. But she mischaracterized the discrepancy in a way that also falls victim to androcentrism. (In saying this I mean no insult to her feminist credentials. Even the best of us have lingering androcentric biases.) The discrepancy isn't between orgasm and intercourse but between clitoral stimulation and vaginal stimulation. Only 25% of women reliably achieve orgasm with vaginal stimulation, but 95% of women can achieve it with clitoral stimulation. But this is only a gap between orgasm and intercourse if you assume that intercourse means vaginal intromission. This Clintonesque definition of sex is clearly androcentric, indeed, phallocentric. Moving past it can only improve our understanding of evolution.

This is an excellent book, and it makes an important point, but it has a number of quirks. My biggest complaint is that little space was devoted to analyzing the bias behind this science and to methodological issues in general. The bulk of the book is spent critiquing the existing models. Only in the last chapter do we get a discussion of how bias led to these models and what the role of bias should be in science--in short, the actual philosophy. The structure of the book is also peculiar. Since the argument has such a clear logical structure, it would make sense to pattern the book the same way. Instead we get odd digressions. The accounts being critiqued occur in chapters three, four and seven. In between we get a discussion of adaptationism and a survey of the account Lloyd likes. I also had trouble individuating accounts at times. (Does Morris present one account or two?) Nowhere is there simply a list of the 20 accounts she critiques, although there is a list that covers 18 of the 20. This book also had a long gestation period, which makes parts of it seem weirdly dated. Lloyd started working on this material 20 years ago and published a major paper on it in 1993. A lot of space is devoted to refighting a battle led by Stephen Jay Gould in the pages of Natural History in 1987. This time capsule quality is in part responsible, I think, for the neglect of recent bonobo research.

I recommend Lloyd's book to all philosophers of biology and students of human evolution. I plan to use it in an upper level undergraduate course in the philosophy of biology next spring. I also recommend much of the Internet discussion that has occurred on this topic, and the related topic of a study by Dunn et al showing that ability to orgasm is about 45% heritable. Lloyd discusses the study on the weblog Philosophy of Biology. Anthropologist John Hawks also has some interesting reflections on John Hawks Anthropology Weblog (on heritability and Lloyd).

 Rob Loftis, Ph.D., Department of Philosophy, St. Lawrence University



April 29, 2005

God's gift to women

From a Darwinian standpoint, female orgasm may be as frivolous as male nipples


Why, o why? It's been 52 years since scientists first considered the female orgasm a legitimate object of scrutiny (thank you, Dr. Kinsey). But they still can't settle on its raison d'être. Theories abound on how this intensely pleasurable pelvic reflex -- which is overwhelmingly, though not exclusively, enjoyed by humans (a few other female primates can climax) -- contributes to the survival of our species. And because each explanation affects how we think about "natural" female sexuality and relations between the sexes, feminists have been eager participants in debates. But most evolutionists -- feminist or not -- aren't keen to embrace the idea that the female climax could be entirely without evolutionary benefit. No matter how obsessively and doggedly pursued in the bedroom, it may be as frivolous as, say, the male nipple.

No one questions the point of male orgasm. It's obvious -- climax and ejaculation are the same for men. But female ecstasy isn't self-evidently linked to procreation. Women don't need to feel the earth move in order to get pregnant. And the majority of those asked by Alfred Kinsey, William Masters and Virginia Johnson, Shere Hite and other prominent sexologists reported that they don't regularly climax during intercourse. In fact, between five and 10 per cent don't enjoy the big O at all.

But let's not permit the facts to get in the way. As Indiana University philosopher Elisabeth Lloyd points out in her new book The Case of the Female Orgasm (Harvard), the well-documented "orgasm/intercourse discrepancy" isn't the only hard evidence about female sexuality to be overlooked by evolutionists. Citing this, male bias and the undefended notion that female orgasm is adaptive (that its evolutionary purpose is to ensure the long-term survival of the species), Lloyd knocks down all but one of the 21 existing explanations. Along the way, she makes a critical distinction between sexual arousal, which she says is critical in evolutionary terms because it makes women want to have sex (and thus results in pregnancy), and female orgasm, which she argues is merely a bonus.

British zoologist Desmond Morris took the first stab at accounting for the pinnacle of female pleasure, in 1967, with the publication of The Naked Ape. Female orgasm, he opined, was ultimately a way to shore up the hunt: because orgasms are a "reward" for "pair-bonding," women were unlikely to be promiscuous, freeing men for days on end to stalk game without worrying that their gal might shack up with a non-hunting wuss. Morris also suggested the much-touted anti-gravity theory. Orgasm, he reasoned, both satiates and exhausts the female, causing her to recline immediately after copulation, and thus increases the chances of fertilization. The trouble is, Lloyd argues, it's men who are satiated and exhausted by sex: women are usually left wanting more -- a state that might, she speculates, have led our feminine ancestors to get out of bed and go cruising.

Competing theories since Morris's remain committed, for the most part, to the notion that women's supreme sexual gratification serves some grand evolutionary purpose. Female orgasm, it's been argued, enhances the emotional connection between partners, making women want to cook and care for their men. Another theory holds that it motivates women to have lots of intercourse with the same man, thereby improving the chances of fertilization; a counter explanation suggests it motivates them to have lots of sex with different suitors, thereby increasing the number of guys who, not knowing if the offspring is theirs or not, won't hurt or kill the babies. Alternatively, some researchers suggest orgasms indicate which fellows will be good caregivers (if he's evolved enough to bring you to the heights of passion, surely he'll look out for the kids, too).

Others emphasize the individual physiological benefits that also contribute to the species' Darwinian struggle. Female orgasm, according to one account that any orgasmic woman would readily corroborate, is therapeutic, relieving the pelvic vascular congestion brought about by fooling around. Then there's the "upsuck" theory, which claims a woman's orgasmic contractions from one minute before ejaculation to 45 minutes after help usher the sperm (and, in one version, only the desirable sperm) to their target -- an explanation familiar to couples undergoing fertility treatment.

Author Lloyd contends all these scenarios lack scientific rigour. To her, the "most illogical" was published in 1979 by William Bernds and David Barash. Here (and elsewhere) her book is a little tough going for those not steeped in evolutionary method. The two cited a tenuous link between rate of orgasm and spontaneous abortion, suggesting a selective advantage to especially responsive females: in the nasty, brutish and short world of our ancestors, where infants of women taken as spoils of war were possibly killed, such abortions would be a shrewd evolutionary strategy. The authors based this theory on a fascinating feature of the female rat, who reabsorbs fetal tissue if an unknown male rat comes on the scene, thus saving the potential litter from being killed by the stranger.

Scholars Richard Alexander and Katharine Noonan strain credulity even more, arguing that the actual orgasm isn't critical to this process. Rather, a woman's moans, gasps and other utterances that convey she's climaxing are all that matters. That's because a smart (and suspicious) mate who believes his partner is carrying another man's offspring will pleasure her in order to induce an abortion. But given the health risks of spontaneous abortions to the mother, Lloyd counters, an equally astute partner would simply pretend to reach her zenith. Alexander and Noonan, it turns out, have only figured out (on dubious premises) why faking an orgasm makes evolutionary sense.

Rejecting all of the above, Lloyd settles on the unpopular but, she insists, most scientifically solid theory available. Around the time the abortion-as-survival-strategies were brewing, University of California evolutionary psychologist Donald Symons proposed female orgasm is nothing more nor less than a by-product of the early stages of a human embryo's development. Fertilized eggs, male and female, share the same physiological characteristics for the first eight weeks after conception, at which point the male embryo releases hormones that kick-start the development of different sexual organs.

Because male orgasm is so crucial to the species' regeneration, all the necessary equipment is present from the beginning. Not only do the penis and the clitoris start out from the same organ, but so do the relevant nervous and erectile tissues. From an evolutionary perspective, female orgasm is superfluous. Women are so endowed, in Symons's reasoning, purely by virtue of our beginnings as undifferentiated beings. (The same theory, on the grounds that breast-feeding is critical to our survival, is widely held to explain the male nipple.)

So what are we to make of the fact that women may be getting a free ride? Lloyd suggests that it helps explain a lot about women's sexual behaviour, most notably the wide range of orgasmic experience. If the species doesn't depend on it, we can all relax: there isn't a single natural or optimal model, and neither frigidity nor promiscuity is dysfunctional. Further, considered alongside studies of two Polynesian communities where all women reportedly climax, she writes, the by-product explanation suggests that ultimately female orgasm may be an acquired response, an innate capacity that women can learn to turn on or off.

Lloyd hasn't written off the possibility that an "obscure" and "exquisitely designed" Darwinian function has yet to be discovered. But for now, she makes a convincing case that from an evolutionary perspective, female orgasm is just the icing, not the cake.




at George Mason University



Come Again?
11:14, June 10 2005
The science behind female orgasm



Elisabeth Lloyd's views on the new heritability study of female orgasm

June 9, 2005









Evolutionary Psychology 3: 347-354

The Human Nature Review

Let a Thousand Orgasms Bloom! 

A review of The Case of the Female Orgasm, by Elisabeth A. Lloyd. 2005. Harvard University Press: Cambridge, Mass. 311 pp.

David P. Barash, Department of Psychology, Box 351525, University of Washington, Seattle, Wa. 98195, USA.


Read these articles, here                                        

You can read an excerpt of the book here