Tag Archives: pregnancy

Your chance of getting pregnant if raped…

… goes down, compared to other forms of insemination, because “the female body has ways to shut that down.” That’s according to Missouri Congressman Todd Akin. But this only works, according to him, if the rape is “legitimate.” From this we can easily develop a sort of Witch Hunt method to determine if a woman accusing a man of rape was actually, “legitimately” raped or if she’s faking it. If she becomes pregnant from the rape, the rape did not happen.

Is this clear?

OK, now that we have that straight, allow me to bring out this one piece of data I thought I’d never have use of. It is a very limited piece of data, not very useful for a large number of reasons. The question at hand can be divided into two parts: 1) What is the chance of a given intromissive internally insemnating sexual event leading to a pregnancy in a woman not on birth control of average fecundity? Then, 2) Does this probability go down, as the good Congresman claims, or does it stay the same.

The answer to the first question is that it is not terribly high. We are not a one-copulation=one baby species. It takes a bunch of tangos to turn out a tyke, on average (but statistics is NOT a birth control method!). As to the second question, it turns out that according to certain data it actually goes up. It is reasonable to suggest that the chance of a single copulation leading to pregnancy if that copulation is rape is about double the overall average. Maybe.

This has been discussed by Thornhill and Palmer, authors of the controversial book “A Natural History of Rape: Biological Bases of Sexual Coercion” and subsequent to the storm of debate that arose from that it has been looked at more carefully and a little bit verified (see this).

I can very easily suggest explanations for this and I can also cast more doubt on the studies. First, the doubt. We have no idea what the actual relationship between having sex and having babies is. One would think we would know, but we don’t. Sure, sex leads to babies and all that, but how many sperm, or how many ejaculations, or whatever, does it take before a single sperm is allowed access to the ovum leading to a pregnancy? Scientifically speaking the research needed to answer this question has not been done. There are no controlled studies in which a sufficient sample of subjects across a range of fertilities (and varying in other appropriate factors) repeatedly have sex with everything carefully measured and controlled. Not one study has done this. I don’t expect there to be one any time soon. Our estimates of fecundity are based on reported data, vague estimates, and a lot of thumb sucking. So, when we have a couple of rape-related studies that show a higher pregnancy rate than background, unless it was a lot higher, we would need to take that with a grain of salt.

But if there really is a higher chance of pregnancy resulting from rape, this still may not mean much. There are a number of reasons this could happen, some of which are discussed in the above mentioned book. One very distinct possibility is that rapists are selecting victims somehow, perhaps with their Darwinian wiles, as it were, or perhaps for purely random reasons, who are slightly more fecund than the larger sample from which the baseline statistic is calculated. In any case, the difference is not large.

But, there it is also not lower. The chance of pregnancy from what the Good Congressman calls “legitimate rape” … a term that will surely live in infamy … is not lower. It might be higher. But it is not lower. The man is an ignorant fool. He is wrong.

Here he is being wrong:

Hattip Kent Jones.

Added: Here’s an idea, ask that this dude be relieved of his duties on the House Science and Technology Committee. Which, amazingly, he is on.