Finger-length as an index of assertiveness in women

A gene causing the index finger to be shorter than the ring finger is said to be dominant in men but recessive in women, with the result that more women have longer forefingers than men. Since this finger-length ratio varies considerably within sex, the possibility that it might relate to masculinity-femininity of social behaviour in women was investigated. Nine hundred and eighty-five women provided self-reports on the length of their fingers and their degree of assertiveness, without knowledge of the hypothesized link. Women whose forefinger was shorter than their ring finger were more likely to describe themselves as ‘assertive and competitive’ than women whose forefinger was longer than their ring finger. This finding could reflect the simultaneous effect of prenatal sex hormones on body and brain.