Sexual Orientation and Gender Identity After Prenatal Exposure to the Dutch Famine

Sexual differentiation of the human brain has been suggested to take place through exposure to sex steroids during intrauterine development. Animal experiments have shown that interference in this process by underfeeding of the mother can result in feminization of the male offspring. We explored the possible effects of prenatal exposure to famine on sexual orientation and gender identity in humans. We used the Klein Sexual Orientation Grid to assess sexual orientation and also assessed gender identity in a group of 380 men and 472 women who were born as term singletons around the time of the 1944-1945 Dutch famine. Prenatal exposure to famine did not affect sexual orientation in men or in women. Three people indicated having some gender identity problems: one woman born before the famine and one man and woman exposed to famine in late gestation. In men, a later birth order was associated with a non-exclusively heterosexual identification. In conclusion, we found no evidence for a significant association between exposure to famine in utero and altered sexual orientation and gender identity. The small sample size of participants with non-exclusively heterosexual identification (possibly due to underreporting of homosexuality) may have reduced our power to detect any differences.