We study the effects of sons versus daughters on parental joint time allocation between the labor market and the household. Using data from the China Health and Nutrition Survey from 1989 to 2006, we apply a fixed-effects model to control for cross-household heterogeneity in son preference. We find that the birth of sons rather than daughters significantly reduces maternal time spent on household chores, which we argue represents an increase in maternal intra-household bargaining power. However, the effects of sex composition of children on paternal time allocation and maternal time on labor-market activities are weak or mixed. Results are robust to a series of sensitive analyses.