Finger-length ratios and sexual orientation (pdf). (2000) Nature 404:p455
In which we learn that the size of your fingers correlates to sexual hormone production and possibly sexual orientation. This is great for party conversations – we hear that even the Pope himself tried this one out.
FIRST PARAGRAPH: Animal models have indicated that androgenic steroids acting before birth might influence the sexual orientation of adult humans. Here we examine the androgen-sensitive pattern of finger lengths, and find evidence that homosexual women are exposed to more prenatal andro- gen than heterosexual women are; also, men with more than one older brother, who are more likely than first-born males to be homosexual in adulthood2, are exposed to more prenatal androgen than eldest sons.