and the “semen replacement theory”
Every woman should know about the “Semen Replacement Theory”
These excellent featured illustrations (above) depict the workings of the “semen displacement theory,” which is explained in the book, Why Is The Penis Shaped Like That? And Other Reflections On Being Human (Part I, page 20).
“We may prefer to regard our species as being blissfully monogamous, but at least some degree of fooling around has been our modus operandi for at least as long as we’ve been on two legs.”
Every woman encountering an uncircumcised penis – especially if living with one – should know about the “upsuck, house cleaning, modus operandi” of this very specialized feature. We can’t cover it all here so for more on the fascinating details read the Book Review #65 and for everything else, buy the book.
However, for more on female orgasms, we’ve provided this excerpt from Part V, particularly the six “Clues.”
The Case of the Female Orgasm (6 min read)
I’ve written at some length about the curious evolution of the male reproductive system in our species, so it’s only right to devote some time to the natural origins of a biological mechanism that doesn’t involve the Y chromosome. (Well, at least it doesn’t have to.) Needless to say, the subject of female orgasms isn’t exactly my cup of tea. Being a gay man, I’ve always thought of the female orgasm as rather exotic and foreign, sort of like decorative basket weaving in a small African village. I could be wrong about this, but as far as I know, I’ve never even been in the same room as a woman having an orgasm, let alone given a woman one. So with that in mind, let’s have a look at what’s happening with those whose orgasmic bliss isn’t neurologically grounded in something that protrudes seven inches (or so) [average penis size 6 inches] from the rest of their bodies.
Fortunately, a handful of dedicated researchers have spent a lot more time on this issue than I have. Yet it’s fair to say that even these scientists are still scratching their heads over the evolution of the female orgasm. Before we get into the nitty-gritty, let’s make sure we’re all on the same page about what a female orgasm actually is. A good working definition can be found in a report in the Annual Review of Sex Research. According to the psychologist Cindy Meston and her colleagues:
Female orgasm is a variable, transient peak sensation of intense pleasure, creating an altered state of consciousness, usually with an initiation accompanied by involuntary, rhythmic contractions of the pelvic striated circumvaginal musculature, often with concomitant uterine and anal contractions and myotonia that resolves the sexually induced vasocongestion (sometimes only partially), generally with an induction of well-being and contentment.
Actually, in light of that description and sans the female bits, perhaps it’s not entirely foreign to me after all. In fact, in terms of evolutionary function, women having orgasms with men is almost as puzzling as men having orgasms with men. How many of us human beings were conceived in the wake of our mothers having orgasms may never be known, but the same mystery doesn’t surround our fathers’ orgasms that day. Unlike men, women don’t need to have an orgasm in order to propagate their genes.
So, from a biological perspective, the “adaptive function” of the female orgasm is still hotly contested. Some theorists, including the late and legendary Stephen Jay Gould, have claimed that it serves no purpose at all but is instead only a quirky, functionless by-product of the ejaculatory response in males. In one of his more provocative essays, “Male Nipples and Clitoral Ripples,” Gould fleshed out an old argument first made by the anthropologist Donald Symons. In 1979, Symons noted that early in embryological development, males and females share the same basic body plan. As a serendipitous consequence of selection for male ejaculation (which in straight men serves obvious reproductive purposes), some of the shared connective tissue and nervous system pathways in females were “accidentally” shaped for pleasure by evolution, too, leading happily to the occasional orgasm in sexually mature females. The clitoris is essentially the female version of the penis, since the two derive from the same embryological substrate. This also explains why female orgasms are achieved more by clitoral than vaginal stimulation.
Lest you think the by-product hypothesis was propagandistic, cooked up in some musty faculty lounge by ivory-tower misogynists, note that for years the main advocate of this position has been a female philosopher of biology named Elisabeth Lloyd. In fact, it was Lloyd who had initially given Gould his lead on Symons’s thinking on the subject and who would later write a book strongly endorsing the by-product hypothesis called The Case of the Female Orgasm. Lloyd’s book was roasted by many evolutionary thinkers because of the not-so-subtle feminist undertones in her writing; basically, she argues that female carnal bliss has been liberated from the ugly realities of reproductive biology. Her position? Ladies, go out—or stay home alone, your choice—and enjoy yourselves, your sexuality is about more than just baby making. But over the years, other empirically minded detectives have been working on this case as well, and many have begun to question the by-product account, claiming instead that the evidence does indeed point to a possible adaptive function of female orgasm.
To help you play along in the role of orgasmic sleuth, here are a few suggestive clues that researchers in this area have been trying to piece together into a plausible evolutionary story:
Clue #1: Twin-based evidence shows that orgasm frequency has a modest heritable component. Uncomfortable as it may be to think of your flush-faced grandmother moaning in ecstasy, there is a clear genetic contribution to female orgasm. Hereditary factors account for only a third of the population-level variance in female orgasm, however.
Clue #2: Most women report that they are more likely to experience an orgasm while masturbating than during sexual intercourse with a male partner, and importantly, such masturbatory orgasms do not always hinge on simulating penile-vaginal sex. However, as the evolutionary psychologist David Barash notes, “just because something (e.g., female orgasm) can be achieved in diverse ways (e.g., masturbation) does not argue against it having evolved because it is particularly adaptive in a specific, different context (e.g., heterosexual intercourse).”
Clue #3: Educated women are more likely to report having masturbatory orgasms—but are no more likely to experience coital orgasms than are less educated women. Religiosity is another social mediator: religious women tend to have less frequent orgasms than nonreligious ones (or at least they report having fewer).
Clue #4: Using self-report data collected from college-aged American females, researchers such as the psychologist Todd Shackelford and the biologist Randy Thornhill have uncovered a positive correlation between frequency of orgasm and the physical attractiveness of male partners, with attractiveness being measured by subjective ratings as well as by indexes of facial symmetry. Recall that in “genetic fitness” terms, attractiveness tends to correlate positively with health and overall genetic value.
Clue #5: There is some physiological evidence that female orgasm leads to the retention of more and/or better-quality sperm among a single ejaculate. I don’t think I can put it any better than the psychologists Danielle Cohen and Jay Belsky: “During the female copulatory orgasm the cervix rhythmically dips into the semen pool, thereby increasing sperm retention (by about 5 percent) relative to intercourse without orgasm, along with the probability of conception.” But as Lloyd points out, most references to these classic “data” on the “uterine upsuck” properties of female orgasm derive from a single participant and were part of an old study done back in 1970. Nevertheless, tellingly, a woman’s “desire to conceive” leads to more frequent self-reported orgasms during sex, and female orgasms are also most likely to occur during the most fertile period of the menstrual cycle.
Clue #6: In a provocative study by the psychologists Thomas Pollet and Daniel Nettle, Chinese women who were dating or married to wealthy male partners reported having orgasms more frequently than women whose partners made less money. That is to say, male partner income correlated strongly and positively with female orgasm frequency, and this income effect panned out even after the authors controlled for (ruled out) a host of extraneous variables, including health, happiness, education, the woman’s personal income, and “Westernization.” In any event, if we were to employ Pollet and Nettle’s theory to other species, women may not be the only females in the animal kingdom whose orgasms are linked to the status and wealth of their male sexual partners. Japanese macaque females display the “orgasm-like” clutching reaction more often when they’re mating with high-status males. There’s no data yet on whether or not they also bite their lower lips in the process.
Together, these findings seemingly vindicate Barash, a vocal critic of Lloyd who, in fact, has been arguing that female orgasm “is a signal whereby a female’s body tells her brain that she is sexually engaged with a [socially] dominant individual.” Pollet and Nettle speculate that female orgasm may be linked to male income because money (resources) is a reliable indicator of the male’s long-term investing in offspring and it may also reflect desirable underlying genetic characteristics. In this light, female orgasm may serve an emotional bonding role, motivating sexual behavior—and hence conception—with high-status males. This is one way to interpret those data, of course, but you may have some other ideas of your own. High-status males typically have higher self-esteem than other men, for instance, which possibly translates to their being better, more secure lovers in the boudoir. In other words, it could be that the men’s actual behavior in the bedroom matters more than their social capital or their net worth.
As you can see, the natural origins of female orgasm remain somewhat mysterious. Some of the findings and logic favor the by-product hypothesis, whereas recent data on male quality and orgasm frequency cast reasonable doubt on the “functionless” accounts. What’s more, female orgasm is unfortunately one of those questions that do not easily lend themselves to controlled experimentation in the laboratory. One can’t, of course, randomly assign women to have sex with males differing in status and attractiveness to see if they climax or not. There are many other important avenues left to explore too, including whether orgasms in lesbians, for example, are tied to similar partner attributes as those above, or whether there’s a different pattern with orgasm among gay women altogether.
I do wish there were a climax to the story and that I might satisfy you, but unfortunately this one doesn’t have a tidy ending. As we’ve seen, some of the greatest minds in modern evolutionary biology have put their heads to the pleasure-filled pudenda, with astonishingly little success (or at least agreement). So in the end, I’m afraid I must leave it to you, dear readers, to piece together a once-upon-a-time story of female orgasm featuring the clues you’re left with.
Why Is the Penis Shaped Like That?: And Other Reflections on Being Human by Jesse Bering