This paper models fertility as the outcome of gender-biased technological progress interacting with endogenous social norms governing childcare. When rising female wages outpace norm adjustment, the inherited norm makes reallocating childcare toward fathers costly, so mothers bear a disproportionate burden and the shadow price of children rises. In cross-country data, fertility falls faster where women's relative standing rises, especially where norms are tighter or more rigid. Calibrated to South Korea (1976–2016), the model shows that strong, slow-adjusting norms deepen the decline. Despite smaller short-run effects, male childcare subsidies yield larger long-run gains than female subsidies by accelerating convergence to egalitarian norms.
