After years of debate, and women just being, like, duh, scientists have finally come to agree that the female orgasm exists. And yet this poses an even more vexing question: Why?

But, obviously, we don't mean to perpetuate the stereotype of scientists as a bunch of virgins in lab coats being all like What is this... female... you speak of? There are, indeed, women scientists these days, and some of them are similarly baffled by the female orgasm, not that they'd look a gift horse in the mouth, or anything. You see, there's no real evidence that the orgasm is an evolutionary adaptation:

[I]f female orgasms are an important evolutionary adaptation, they should be easier to attain. Also perplexing is that many women require clitoral stimulation to achieve orgasm, not penetrative action. If female orgasms were meant to encourage sex, the opposite ought to be true.

So, hmm, you can see why scientists just don't "get" the female orgasm, in a scientific way. In The Case of the Female Orgasm, author Elizabeth Lloyd—building on the work of others—posits that it's, more or less, a happy accident, a byproduct of the fact that women "share biology with men." But a recent study of opposite-sex twins would seem to put this theory to rest, too:

[Geneticists Brendan Zietsch and Pekka Santtila] surveyed 1,803 pairs of opposite-sex twins and 2,287 pairs of same-sex twins, asking them how often and how easily they reached orgasm. If female orgasm is evolutionarily connected to male, opposite-sex twins should have similar orgasmic function.

But that's not what they found. Instead, while orgasmic function was genetically shared in same-sex twins - brother tended to share function with brother, or sister with sister - the relationship vanished in opposite-sex twins, though both share the same amount of genetic material. The underlying genetics, and thus the underlying evolutionary pressures, thus appear to differ.

So, does that mean the female orgasm does have an evolutionary rationale? Or is it just another scam perpetrated by Big Vibration? "The evolutionary basis of female orgasm is both important and unknown," write the researchers. "Much more work needs to be done." That's what she said.

[Wired; image via Shutterstock]