Previous studies of non-human animals and humans with endocrine abnormalities have demonstrated that higher prenatal androgen levels promote more male-typical behavior, including cognitive abilities and sexual behavior. Research on normal hormonal fluctuations (e.g. menstrual cycle studies) has shown additional effects of circulating sex hormones in postnatal life on the expression of a number of sex-linked cognitive and sexual behaviors. This research was designed to replicate previously reported sex differences in a variety of domains and to extend prior findings of an association between low (male-typical) 2nd to 4th digit (2D:4D) ratio, enhanced (maletypical) mental rotation ability, and more liberal (male-typical) sexual attitudes and behavior in women. This is also the first study to examine the effects of hormonal factors and other sex-linked variables on sociosexuality in men. As part of this study, participants (n = 127) completed a battery of gender role measures, sex-linked cognitive tasks, and a sexual attitudes questionnaire. Prenatal androgen levels were indirectly measured by means of the index to ring finger (2D:4D) ratio, and testosterone and progesterone levels were obtained from saliva samples collected at each session from participants who were not using hormonal contraceptives. Results replicate previously reported sex differences in sexual attitudes, sex-linked behaviors and personality traits. More importantly, results provide the first evidence for both pre- and postnatal contributions to sexual attitudes. Men with lower (more male-typical) 2D:4D ratios reported less restricted (more male-typical) sexual attitudes, suggesting that prenatal hormone levels may influence sexual attitudes in adulthood, at least in men. Additionally, the tendency for women who were not using hormonal contraceptives to report less restricted sexual attitudes during the mid-luteal phase of their cycle than during the menstrual phase suggests that changes in circulating sex hormone levels in adulthood, such as those during the menstrual cycle, may influence sexual attitudes in women.
