A SYTYCB entry
The views of the doctor behind Todd Akin’s screwed up understanding of biology, John C. Willke, have been dismissed by ob/gyn experts.  Nevertheless, Willke’s claim that pregnancy from rape is rare continues to be cited as medical fact, despite evidence from peer-reviewed studies to the contrary .
Out of curiosity/masochistic tendencies, I took a closer look at Willke’s 1999 article, “Rape Pregnancies Are Rare.” The article was published in Life Issues Connector, a newsletter of the Life Issues Institute. It is not a peer-reviewed publication, and Willke’s article would never see the light of day in any respectable medical journal. It is an agenda-pushing screed dressed up in math with unsubstantiated statistics.
Willke’s shady math uses a lot of numbers for which no sources are listed. Among the salient errors of Willke’s article are:
- Citing “approximately 100,000,000 females old enough to be at risk for rape in the United States.” No source is cited for this number, and Willke doesn’t define what age he believes would make a female “old enough to be at risk for rape.” The fact that he’d even use this phrase shows how little he knows about rape, as victims include both infants and the elderly.
- Factoring in that “[o]f the… women who were forcibly raped, one-third were either too old or too young to get pregnant.” Again, no source is provided, and since Willke doesn’t describe how he comes up with this ratio, it’s not possible to examine his underlying assumptions to assess their validity. What ages did he consider “too old” or “too young”? Did he assume that the ages of rape victims were evenly distributed (a common error for calculations like these)?
- Adjusting incorrectly for infertility in men and women. Willke cites a figure of 15% of men being infertile and 15% of women being infertile, and adjusted his calculations by deducting 15%, and then deducting 15% again from the resulting figure. (No source is provided for these infertility rates.)
The Mayo Clinic cites a rate of 15% infertility for couples, with male infertility playing a role in about half of these cases . Thus Willke adjusted twice for a 15% reduction when he should have adjusted only once.
- Counting things twice. One overall problem with Willke’s simple math is that he lists different factors/ statistics and adjusts for each item in a serial fashion as though they are completely independent of each other. Thus he over-adjusts, for example, when he also factors in “the fact that it takes 5-10 months for the average couple to achieve a pregnancy” by dividing by 5 or 10. But he’s already separately adjusted for the percentage of time a woman is fertile during each of her periods, which is interrelated with how long it takes for couples to achieve pregnancy.
- Making up numbers entirely, like “20% of raped women miscarry.” He also slaps on a 50% reduced chance of pregnancy due to the physical trauma of the rape, without any justification whatsoever. Although he doesn’t even pretend to know that these numbers are correct, his final calculation and conclusion of “extremely rare” rely on them.
Other numbers (e.g., for proportions of women who are sterilized or already pregnant or on the pill) are also cited without sources or any details. So it’s not possible to check that he’s using the correct numbers and avoiding mistakes like double-counting.
A good science article shows you where the numbers come from and states the assumptions, so they can be properly assessed. What’s sad is that while reasonably educated people who take the time can see through Willke’s number-fudging, his false conclusions have taken hold and continue to be propagated as medical fact among GOP and other extremists.
 Belluck, Pam: “Health Experts Dismiss Assertions on Rape,” New York Times, August 20, 2012, accessed at here.
 Holmes et al: “Rape-related pregnancy: Estimates and descriptive characteristics from a national sample of women,” American Journal of Obstetrics & Gynecology, Volume 175, Issue 2 , Pages 320-325, August 1996. Abstract available here.
 Male infertility, Mayo Clinic website.
(Cross-posted at impropaganda.blogspot.com)