Today’s Course in Home-Schooled Women’s Biology
Update: Los Angeles Times, August 6:
The dilation of pupils in response to erotic stimuli may be the most accurate objective measure of an individual’s sexuality, researchers reported Monday…
The findings support the idea that sexual response has different biological functions in men and women. For men, an important function is to facilitate erection and penetration. For women, the function is to stimulate lubrication and prevent genital injury in case of penetration — a response that may have developed early in evolutionary history in response to episodes of rape by males.
The study, by Gerulf Rieger and Ritch C. Savin-Williams of the department of human development at Cornell, is from PLoS One journal, August 3:
Among heterosexual participants, substantial sex differences in pupil response were found. Compared to heterosexual men, heterosexual women showed a more equal sexual response to male and female stimuli. This sex difference is consistent with previously reviewed theoretical writings and documented sex differences in genital response. Baumeister argued that the sexes evolved to differ in their sexual responsiveness, and this is an adaptation to the sexual behavior of the other sex. One hypothesis related to Baumeister’s proposal is that sexual response has different biological functions for men and women. For men, an important function is to facilitate erection and penetration; for women, to facilitate lubrication and prevent genital injury in case of penetration. Support for this hypothesis is derived from both cross-species and cross-cultural comparisons. Forced copulation in several species and in most human societies indicate that it may have occurred throughout human evolution. Because forced copulation can lead to genital trauma, the female response to any sexual stimulus may have evolved in part to mitigate this risk.
If our hunch is correct about Todd Akin’s ultimate source, the point of the article is not that women’s bodies can resist impregnation in cases of rape, but that they have evolved to cope with it. But the coping does not affect fertilization.