Recently Rep. Todd Akin (R-MO) made a very bad gaffe. It is pretty serious and you might have already heard about it. The quote in question as made during an interview with KTVI on Sunday was:
“If it's a legitimate rape, the female body has ways to try to shut the whole thing down."Now a lot of people have been very upset about the phrasing of "legitimate rape" and rightfully so (you can already buy "illegitimate rapist" T-shirts). But that's not what I want to write about. I want to talk about the myths regarding pregnancy and rape. There actually is science that has been done specifically on this problem, and as it turns out the opposite is true. Researchers have found that the "per-incident rape-pregnancy rates exceed per-incident consensual pregnancy rates by a sizable margin." (Gottschall & Gottschall, 2003).
The Gottschalls set out to re-evaluate the data gathered by medical and public health professionals regarding the medical and psychological health of rape victims. By carefully screening this data the researchers were able to come up with meaningful comparisons between consensual (albeit unprotected) sex pregnancy rates and rape-pregnancy rates. After adjusting for contraception use the per-incident rate of pregnancy resultant from rape is about 8%. This is compared to the consensual, unprotected intercourse was calculated at 3.1% (Wilcox et al., 2001). But how can we explain that?
One possible explanation is that women, somehow, broadcast their fertility. That is to say that men can tell when women are ovulating, and that this is arousing, and thus triggers the rapist to strike. While there is evidence that men can detect when women are ovulating, I still don't think that fits well here. In general rape is considered a crime of violence not passion. It is about dominance not reproduction. But even still there may be some link between increased arousal and violence in men. A better supported explanation is that of coitus-induced ovulation. This is like what happens in cats; a significant vaginal stimulation triggers ovulation. In fact the very stress of being raped may trigger ovulation. Researchers were able to show that acute stress can trigger ovulation at any point of the menstrual cycle (Tarin et al., 2010).
Certainly more research is to be done on these and other potential mechanisms of this phenomenon. Even still I think it is important for politicians (and all of us) to use the science that is available to us. There is research that we can use to help inform public policy and I feel it is dangerous for us to ignore science.I don't know what this means for Todd Akin (I'm not a political science professor) but hopefully he'll read some science for next time.
Jonathan A. Gottschall, & Tiffani A. Gottschall (2003). Are per-incident rape-pregnancy rates higher than per-incident consensual pregnancy rates? Human Nature, 14 (1), 1-20 DOI: 10.1007/s12110-003-1014-0
Tarín JJ, Hamatani T, & Cano A (2010). Acute stress may induce ovulation in women. Reproductive biology and endocrinology : RB&E, 8 PMID: 20504303 Wilcox AJ, Dunson DB, Weinberg CR, Trussell
J, & Baird DD (2001). Likelihood of conception with a single act of intercourse: providing benchmark rates for assessment of post-coital contraceptives. Contraception, 63 (4), 211-5 PMID: 11376648