I think the female orgasm may help with fertility. The muscle spasms also affect the cervix and allows semen to be drawn into the uterus.

Not to mention it definitely makes the female more receptive to sex.

Sperm retention. Supposedly this could allow the woman to have some "choice" in which man impregnated her in the event of multiple sex partners.

Baker & Bellis (1993)

I have not read the above study, but it was the source referenced in the book "The Red Queen: Sex and the Evolution of Human Nature" which stated the following:

"They found that in faithful women about 55 percent of the orgasms were of the high-retention (that is, the most fertile) type. In unfaithful women, only 40 percent of the copulations with the partner were of this kind, but 70 percent of the copulations with the lover were of this fertile type. Moreover, whether deliberately or not, the unfaithful women were having sex with their lovers at times of the month when they were most fertile. These two effects combined meant that an unfaithful woman in their sample could have sex twice as often with her husband as with her lover but was still slightly more likely to conceive a child by the lover than the husband."

In a class I took in college, my professor showed us footage from a tiny camera being inserted near the cervix during sex. Upon female orgasm, the cervix literally sucks up the semen closer to it/up into the uterus.

Since female orgasms are usually more 'mind-over-matter" than men, women's ability to orgasm can help select the man that is strongest and would create the most healthy offspring. If she's not feeling it (or him), he's probably not fit to be the father of her children (at least from an evolutionary standpoint) and therefore.. no orgasm and no chance of more semen being drawn up into the uterus.

I think it has to do with mate selection. From an evolutionary perspective, it is advantageous for the woman to have the father of her children stick around to help raise / protect them as opposed to abandoning them when she is pregnant or shortly after she has given birth. A woman is particularly vulnerable at these times.

There are studies that show that women orgasm less in the early stages of a relationship (including one night stands) and more once they have formed an emotional bond with their mate. This makes her more interested in having sex with, and reproducing with, a longer-term partner with whom she has an emotional bond.

I often find it curious that emotions and the motivations that they impart are rarely part of discussions about evolution. Most discussions focus only on the physical. Surely humans did things for emotional reasons 10,000's of years ago just as they do today, so their emotional framework is just as important from an evolutionary perspective as the physical.

i have no idea where i read this, but here goes anyway. during labour women would masturbate and orgasm to help relax the muscles in the vagina. clitoral stimulation makes for easy access. i would think that g-spot ejaculation caused by the baby's head pressing onit would help make the passing of the shoulders more tolerable :))))

I think most speculation I've read on this online is bogus and not well supported--the only part that is persuasive is the oxytocin load...perhaps it served as some kind of birth control, protection from urinary tract infections etc. But now I am speculating.

I also don't buy it's purpose is pleasure...I think the female anatomy probably only served to ensure the conception by lubrication (to encourage the male's you know...emission) or then protect the woman's hormone shifts with the oxytocin load. Maybe we evolved for pleasure over time but I would cite that animals go through instinctual mating...all males obviously orgasm but females (besides dolphins) do not.

I choose to have the orgasm remain mysterious.

I also would not want to have one during childbirth. If they had offered it as an option I probably would have opted for some ice cream instead...or maybe a cheeseburger.

I thought this statement in the article very odd: "It might also have been evolutionarily important to humanity’s ancestors, but irrelevant now."

I would argue quite the opposite -- that it is far more important now. Because women now have a say in who they have sex with (more and more, this is not, of course, universally true), I would guess that those who have the choice, would choose someone with whom they orgasm, thus making it far more evolutionarily important now than to our ancestors.