Is Rape an Effective Reproductive Strategy?

Last year Randy Thornill and Craig Palmer created a controversy with their book, A Natural History of Rape, which argued that rape persists because it evolved as a successful reproductive strategy for some men. Now, Jon and Tiffany Gottschall have added new fuel to the fire with a study suggesting that women who are raped are more likely to get pregnant than women who engage in consensual sex.

The Gottschalls compared two groups of women. Tee first group were 405 rape victims aged 12 to 45 who were interviewed at random as part of the American National Violence Against Women survey. The second group were the subject of a study by Alan Wilcox at the National Institute of Environmental Health Sciences This group included more than 300 women who were not using any form of birth control and had one night stands.

The Gotschalls found that only 3.1 percent of the women who had consensual one night stands became pregnant, while 8 percent of the women who were raped became pregnant. The Gottschalls hypothesize that rapists may subconsciously target women who are more likely to be fertile (i.e. healthy and attractive women).

This study is interesting but there are a number of methodological problems with the study that should keep people from reading to much into it. What is fascinating, however, is the inability of many people to realize what it would imply if there were solid evidence that rape evolved as a successful reproductive strategy.

Many of the people outraged by this study seem to be under the impression that if rape is a successful reproductive strategy that this would imply that rape is justifiable or inversely imply that men are inherently immoral. Hilary Rose, a professor of sociology, told The Times (UK) that the study was dangerous saying, “You end up doing enormous harm and not just to female victims. I think you insult men very deeply by saying that they are biologically prone to rape.”

This is a repeat of the vicious rhetoric that was directed at A Natural History of Rape. But the claim that rape evolved as a reproductive strategy says nothing about whether or not rape is moral or immoral. The only thing that counts from the point of view of natural selection is whether or not an adaptation increases the likelihood of an individual passing on his or her genes.

One of the things that likely developed as a result of evolutionary, for example, is the craving that many people have for foods with high fat content. Such an adaptation served human beings well thousands of years ago, but is definitely not a very successful eating strategy for contemporary industrialized societies.

Unfortunately people conflate “is” and “ought” for two reasons. First, because many of the same people who attack the notion that rape might have arised as part of evolution are more than willing to bring in such evidence if it supports their view. There is an extensive feminists literature, for example, looking at how bonobos monkeys and attempting to extrapolate to human societies (bonobos have a female-dominated social structure). Second, the word “natural” has gradually been imbued with the a positive meaning such that oftentimes in our society people use the word “natural” as a synonym for “good.” The idea that nature might be anything but some happy-go-lucky paradise is becoming increasingly alien in Western cultures as they react against urbanization and industrialization.

Claims about the natural history of rape illustrate the problems with both trends. Evolutionary biology often seems to be anthropologists simply swapping “just so” stories that happen to fit whatever ideological predispositions the researchers have, while the tendency for people to reflexively approve of anything that is “natural” means that what counts as natural becomes more contested in many cases than that counts as moral.


Raped women ‘more likely to get pregnant’. Helen Rumbelow, The Times (UK), June 21, 2001.

Genetic link between rape and pregnancy. The BBC, June 20, 2001.

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