The Effect of Age at First Marriage on Female Fertility: Evidence from Korea’s School Entry Policy Using Exact Date of Birth

Delay in age at first marriage has been hypothesized as a significant determinant of worldwide fertility decline in high-income countries. Testing this hypothesis is challenging because age at first marriage is confounded with unobservable variables such as career aspiration. To overcome the endogeneity issue in the age at first marriage variable, this paper exploits exact date of birth that creates an exogenous variation in school starting age as an instrument for female’s age at first marriage and uses a regression discontinuity design to estimate its impact on female fertility. The statistical analysis based on the 2009 Nationwide Fertility Level and Family Health and Welfare Survey shows that an increase of one year in age at first marriage reduces the likelihood of any childbirth (extensive margin) by about 8 percentage points (10%) and total childbirths (intensive margin) by 0.1 children (6.3%). While delay in age at first marriage reduces fertility, we argue that policymakers should not implement policies to prevent females from delaying marriage timing as many studies have found that there are gains to delaying marriage. Rather, we argue that policymakers should engage more in identifying policy measures that allow the transition to adulthood and participation in higher-education institutions more compatible with motherhood and childbearing.