Sex-specific cognitive costs and benefits in early parenthood.

Research on cognitive changes across the transition to parenthood has primarily focused on mothers and emphasized decline, whereas paternal cognition and its neuroendocrine correlates remain understudied. In this cross-sectional study, we compared cognitive performance in 158 mothers and fathers of infants aged 8 weeks to 6 months with 154 non-parent controls and examined associations with sex and plasma oxytocin and cortisol concentrations. Multidimensional structural equation models revealed no evidence for global cognitive impairment associated with parenthood. Instead, selective and sex-specific patterns emerged: Fathers showed enhanced object perception relative to non-fathers, whereas mothers exhibited modestly diminished working memory as compared to non-mothers. Face memory was positively associated with circulating oxytocin concentrations and with female sex, independent of parenthood status. Plasma cortisol concentrations were not significantly associated with cognitive performance across domains. Sensitivity analyses adjusting for age, sleep quality, depressive symptoms, stress, and hormone sampling time did not substantially alter the overall pattern of findings, although a subgroup-specific association between oxytocin and face memory in males was not retained after adjustment. Together, these findings suggest that early parenthood is characterized by domain- and sex-specific cognitive differences rather than uniform impairment. The results challenge deficit-oriented accounts of postpartum cognition and underscore the importance of integrating fathers and neuroendocrine perspectives into models of cognitive adaptation during early parenthood.