Combining eight years of panel data with an event study approach, we show that rural Chinese womens' labor supply falls for one year following the birth of a daughter before returning to their pre-birth levels. The negative impact of the birth of a son on women's labor supply is much larger in magnitude and persists for four years. We also find that households reduce their consumption of cigarettes more following the arrival of a boy than a girl. Furthermore, there is an increase the probability of being in school and time spent on leisure for mothers following the birth of boys but not daughters. Together, these results are consistent with two mechanisms. First, mothers are rewarded for giving birth to boys, leading them to consume more leisure and work less. Second, households' returns to investment are higher for boys than girls, leading mothers to invest more effort in them.