Sexual orientation of human offspring may be altered by severe maternal stress during pregnancy

To test the hypotheses that maternal stress during pregnancy may alter the sexual orientation of offspring, 285 women with offspring 19 years of age and older provided retrospective accounts of stressful experiences they had, beginning 12 months prior to pregnancy up to the point of giving birth, and indicated how severe they recalled each event being. When weighted according to severity, stressful experiences helped to predict sexual orientation of male offspring. While most of the variance in sexual orientation remained unexplained, the data suggest that the most critical time in gestation for influencing human sexual orientation of male offspring is during the second trimester, although the first and possibly the third trimesters may be of secondary importance. For female offspring, no significant relationships between maternal stress and sexual orientation were found, although mothers of lesbians did report slightly higher average levels of stress throughout gestation than mothers of female heterosexuals.