Intrauterine stress and male cohort quality: The case of September 11, 2001

► Research on fetal survival asserts that males more than females appear sensitive to ambient stressors in utero. ► We tested whether child development is altered among males reportedly affected in utero by the 9/11 attacks. ► Consistent with cohort culling in utero, 9/11-affected males score greater than expected in cognitive ability at 24 months. ► No difference was observed among height-for-age values. ► Population stressors may induce male-specific culling, resulting in relatively improved development among male survivors.