Dragon Children: Identifying the Causal Effect of the First Child on Female Labor Supply with the Chinese Lunar Calendar

Instrumental variables (IV) estimates of the effect of fertility on female labor supply have only been able to identify the causal effect of second and higher-parity children. This study uses exogenous variation in fertility caused by the Chinese lunar calendar to identify the effect of the first child. Additionally, weighting formulas are presented to interpret IV estimates as weighted average treatment effects in the case of multiple endogenous variables, which are useful when children vary in intensity by both number and age. The effect of the first child is found to be much greater than that of other children.