Migration Reform and Fertility: Evidence from Rural China

How do institutional barriers to migration shape fertility in developing economies? We analyze the staggered removal of institutional barriers to rural-to-urban migration across 283 Chinese cities. We find that reducing these frictions led to a significant and persistent increase in fertility in sending rural communities. The average treatment effect is 0.011 newborns per household per year, representing approximately one-third of the sample mean. To interpret this result, we develop a unified household model endogenizing fertility and partial migration. The model identifies a positive income effect (higher expected lifetime earnings) that dominates the substitution effect (opportunity cost of time). Empirically, we show that the fertility response is concentrated in households with available grandparents and prior migration experience. This suggests that informal childcare provision is critical in neutralizing the time costs of migration, allowing rural households to realize the fertility gains from improved economic opportunities. These findings challenge the view that urbanization necessarily reduces fertility, highlighting instead how mobility restrictions acted to suppress fertility.