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.