One of the best theories to date is that the female orgasm is just an "evolutionary leftover," kinda like male nipples. Sexy …

While the role of the male orgasm during sexual intercourse is self-evident from a reproductive standpoint, the exact purpose of the female orgasm has yet to be resolved.

Why? Because on top of the sheer rarity of female orgasm during intercourse, there is absolutely no correlation between orgasm and fertility rates. This makes the female orgasm scientifically enigmatic; if it has no definable function, why does it exist? Sex research is a billion dollar industry, pumping out everything from orgasm pills to gyrating whatchamacallits, yet no one has the faintest clue.

Of course, we’re not talking about female pleasure here. There’s a clear and present reason why sex would feel good, like really good, to women: to increase their reproductive activity. But orgasm is different than pleasure. Orgasm is a climatic response that more closely resembles the male experience.

A popular explanation on the subject is that the orgasm is just a magnificent biological “byproduct” of evolution. Expert in the field and philosopher of science, Elisabeth Lloyd, argues that female orgasms have no function with respect to survival and reproduction. Instead, she believes they are best thought of as evolutionary side effects, like male nipples.

“Magnificent accident”is a great way to put it; however, the truth is that most females still don’t orgasm from sex. Only 25 percent of women are considered “consistently orgasmic during vaginal intercourse” according to Psychology Today. In fact, the overwhelming majority of women are more likely to achieve orgasm alone through masturbation, so from an evolutionary standpoint, what the hell is that about? There’s very little correlation between vaginal intercourse and orgasm, which further negates any direct link between the orgasm and reproduction.

Some of the earliest modern research on the subject focused in on the importance of the sperm remaining in the vagina for a longer period of time, the theory being that orgasm increases the period in which the woman is horizontal, rather than vertical where the pesky “drip” sesh begins. In 1967, zoologist Desmond Morris noted: “There is a great advantage in any reaction that tends to keep the female horizontal when the male ejaculates and stops copulation. The violent response of female orgasm, leaving the female sexually satiated and exhausted, has precisely this effect.”

Exhausted and satisfied, spoken like a regular projecting male. Regardless, the idea holds up on a biological level, in general. As observed by Gordon Gallup and Susan Suarez in the 1980s, “the average individual requires about five minutes of repose before returning to a normal state after orgasm, and some people even lose consciousness at the point of orgasm.”

Black-out orgasms? Yes, please. Although at this juncture, the question of where a blackout orgasm fits into the whole evolutionary schema arises. The pair has successfully mated, the egg’s been fertilized, but now the prehistoric male and female have been rendered unconscious from their orgasm so … so what? So they can be more easily consumed by a Saber-toothed tiger?

But, just when we thought we were making headway,  another scientist materializes, waiting for their turn to nullify the previous hypothesis. Lloyd points out the most effective position for clitoral stimulation (and consequent orgasm) is when the female is on top of the male. In this scenario however, we are faced with the “vertical drip” dilemma and the “draining-effects” gravity has on fertilization odds. Leave it to a group of scientist to make an extensive conversation on “violent” screaming orgasms this un-sexy.

One of the most recent consideration for explaining the evolutionary purpose of the female orgasm is the highly-visual “up-suck” hypothesis (just when you thought this couldn’t get any less sexy). There’s evidence to suggest that pressure in the uterus decreases after an orgasm, creating a “vacuum suction effect,” hypothetically resulting in sperm being sucked into the uterus, increasing the likelihood of fertilization.

Researcher Brendan Zietsch from the University of Queensland believes the orgasm could simply be a form of operant conditioning, regardless of the actual orgasm rates. In an interview with Popular Science, Zietsch explains that the orgasm provides women with an extra “reward” so to speak for engaging in sex, therefore potentially increasing both the regularity of sexual intercourse and also fertility.

On the more relational level, several theories of orgasm suggest that it functions to increase pair-bonding and aid in mate selection (higher quality mates should theoretically be able to bring on orgasm). According to these theories, the couple that orgasms together, stays together, increasing the survival chances of their offspring. However, many couples stay together happily in which the female doesn’t orgasm from vaginal intercourse, and couples don’t stay together simply because they’re able to make each other cum.

And finally, there’s the “rhythmic contraction” hypothesis which says that the waves of muscular contractions some women experience during orgasm propel semen towards the cervix. However, the fact that not all women experience these contractions during orgasm, and that they can also be brought on by clitoral stimulation, make it a poor candidate for describing the actual function of the climax.

We’ve landed on the moon, discovered trace evidence of the Higgs boson yet we still as a species are completely baffled as to the purpose of the female orgasm.

We're sure everyone out there is all worked up after reading this one.

*cues up Ginuwine’s ‘Pony’*