Not really (absence of evidence is poor evidence of absence). Here's a summary of some of the relevant evidence, from last year:
http://www.scientificamerican.com/blog/post.cfm?id=reopening-the-case-of-the-female-or-2009-12-01
The additional uptake of sperm is only 5%. This might make a difference, but it might not be much. I'm guessing that the sperm in the first wave have the best chances, and adding a little more sperm at the back isn't going to do much.
Some more guesses: If it's true that 25% of women are reliably orgasmic, 50% are occasionally orgasmic, and 25% aren't orgasmic, this suggests a single gene, but that would be surprising.
However, it also suggests a mixed strategy. Maybe non-orgasmic women are less inclined to adultery, so their marriages are less likely to ge...
>Elisabeth Lloyd: I don’t actually know. I think that it’s at a very problematic intersection of topics. I mean, you’re taking the intersection of human evolution, women, sexuality – once you take that intersection you’re bound to kind of get a disaster. More than that, when evolutionists have looked at this topic, I think that they’ve had quite a few items on their agenda, including telling the story about human origins that bolsters up the family, monogamy, a certain view of female sexuality that’s complimentary to a certain view of male sexuality. And all of those items have been on their agenda and it’s quite visible in their explanations.
>Natasha Mitchell: I guess it’s perplexed people partly, too, because women don’t need an orgasm to become pregnant, and so the question is: well, what’s its purpose? Well, is its purpose to give us pleasure so that we have sex, so that we can become pregnant, according to the classic evolutionary theories?
>Elisabeth Lloyd: The problem is even worse than it appears at first because not only is orgasm not necessary on the female side to become pregnant, there isn’t even any evidence that orgasm makes any difference at all to fertility, or pregnancy rate, or reproductive success. It seems intuitive that a female orgasm would motivate females to engage in intercourse which would naturally lead to more pregnancies or help with bonding or something like that, but the evidence simply doesn’t back that up.
The whole discussion. It backs my theory that using evolution to explain current traits seriously tempts people to make things up.