Ever Wondered?

Why do women orgasm?

Unraveling the elusive female orgasm

October 14, 2011

There might be nothing more mysterious in the world than the female orgasm. But there is one, big question that science still can’t answer about it: Why does it exist?

Now, if you’re a woman, you probably just said to yourself: “What do you mean, why does it exist?” But hear me out — there is actually a long running scientific debate over why women have orgasms. While the male orgasm is a necessary feature of reproduction, there are loads of species that reproduce successfully without any kind of female orgasm. So why do we have it?

There are three main theories for why women might have orgasms, says Robert King, a researcher at the University of East London.

The first one says that female orgasm is simply a leftover from the male orgasm. Because there was such strong selection for orgasm in the male penis, the female clitoris (the homolog to the penis) simply came along for the ride.

The second theory is that female orgasm reinforces the bond a woman feels with her partner. Orgasm often (but not always) involves the release of oxytocin, which researchers think strengthens pair bonds.

The third theory is that when females orgasm, they’re actually able to preferentially select sperm from some partners over others. This idea, unfortunately named “insuck”, suggests that women can control the movement of sperm into their uterus. This has been observed in horses and pigs before: Basically, orgasm causes pressure changes between the uterus and vagina, sucking the sperm inwards and increasing the chances of fertilization.

Now, insuck is not without its skeptics. The famed Masters and Johnson tried to replicate the first insuck experiment and failed. Others have argued that the logistics of insuck simply wouldn’t work. The male and female orgasm would have to be completely synchronized — and you and I both know that rarely happens.

Between those three theories, no one really knows what’s right. King is skeptical that the female orgasm is simply left over from its male counterpart. It could be a combination of a lot of things, King says. And the fact that it seems like there are two kinds of female orgasm complicates things further. “All of this makes me think that we’re very unlikely to find one answer to the question of what the female orgasm is for,” he says.

So for now, the female orgasm remains one of the most mysterious, and sought after, phenomena on earth.

About the Author

Rose Eveleth

Rose Eveleth graduated from the University of California, San Diego with a B.S. in ecology and a minor in writing. She spent the last four years there poking around in labs, studying krill, climbing trees, riding bikes and perfecting her fish doodles. A sucker for being lost in strange places, she recently wandered her way through Costa Rica, Portugal, Tokyo and Bonaire and is excited to take her wandering to the epicenter of strange places, New York City.



E. Carpenter says:

There is another theory, ignored by an astonishing number of biologists, to explain the presence of both male and female orgasms. And that is the fact that orgasms are intensely pleasurable in both sexes.

The statement in the article that “the male orgasm is a necessary feature of reproduction” is not, actually, correct. The ejaculation of semen is necessary for reproduction, but male orgasms are much more physiologically complex than just ejaculation, and sometimes occur without ejaculation. The entirety of a male orgasm must have other benefits, and must fill other needs, since only the ejaculatory portion of the event is connected to reproduction.

Reproduction is a possible side effect of some sexual activities, and any group which does not engage in at least a small percentage of reproductive sex will die out – but the great variety of sexual practices in the animal world (including humans), and the length of the gestation period in all animals (babies are not an immediate effect of sexual activity), are strong indicators that sexual activity is not engaged in primarily to make babies. An interesting example supporting this is the sexual behavior of giraffes in the wild, which is more often homosexual than heterosexual in both sexes. Out of their entire repertory of sexual activities, though, enough is both heterosexual and potentially reproductive to sustain the giraffe population, at least in the absence of human poachers.

Studies of human motivations for sexual activity reveal that few humans are sexually aroused by contemplating the care of babies or the rigors of childbirth. In the absence of cultural factors and the knowledge of the connection between sex and reproduction (factors which are evolutionarily quite recent), both male and female primates who have pleasurable orgasms are more likely targets for evolutionary selection than male and female primates who do not have pleasurable orgasms.

Vivian says:

To date, the strongest explanation for the female orgasm is indeed the “common fetal body plan” theory. Since human fetuses start out with a common body foundation (which includes the common basic structures of genitals) before differentiating into female/male, the female orgasm is a “vestige” of the the male orgasm — since male orgasm is selected for, and since all humans start out with the common fetal body structures mentioned above, females are able to orgasm because men can (and since there is no evolutionary disadvantages to the female orgasm, it does not get selected out). It’s the same reason why men have nipples — they have nipples because women do, and because the common fetal body plan includes nipples as well (and since having nipples is not disadvantageous for men, this trait does not get selected out).

JP says:

How do we know the male orgasm is not a vestige of the female orgasm? Perhaps the clitoris is selected to be highly sensitive and the development into a penis simply retains the vestige of clitoral pleasure sensations.

MJ says:

JP, we know it isn’t like that because women/females a.) don’t need to penetrate and b.) don’t need to ejaculate. A clitoris, speaking purely from a strictly biological reproductive standpoint, is as useless as the proverbial “tits on a bull”. Humans/primates could never have evolved if they were selected for having a clitoris, unless the clitoris itself is some vestige of a previous form of reproduction. And even if that is the case, clearly primate/human males are selected for having a penis, testis, and the ability to ejaculate. Testes and a clitoris and orgasm without ejaculation would be functionally selected out of the gene pool very quickly.

Oveida Lunsford says:

This theory or ideology just proves that men don’t know anything about the female body nor the types of orgasms that females can potentially gain. It is definitely not as a end result of the male counterpart. There are women in the world who know their bodies well and are able to achieve pleasurable orgasm with or without the male counterpart. Insuck, I think that I understand that process in regards to the orgasm, the tightening and loosening that occurs with or during the orgasm or what occurs between the vagina and the womb. The clitoris developing into a penis, not sure if I follow this thought.

Liz says:

What about women that live their entire lives without ever having an orgasm? Explain that then! Some women have never even felt anything whatsoever from penwtration as well. Not very good for reproduction is it?

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