Fertility Effects on Female Labor Supply: IV Evidence from IVF Treatments

This paper introduces a new IV strategy based on IVF induced fertility variation in childless
families to estimate the causal effect of having children on female labor supply using IVF
treated women in Denmark. Because observed chances of IVF success do not depend on
labor market histories, IVF treatment success provides a plausible instrument for
childbearing. Our IV estimates indicate that fertility effects are: (a) negative, large and long
lasting; (b) much stronger at the extensive margin than at the intensive margin; and (c)
similar for mothers, not treated with IVF, which suggests that IVF findings have a wider
generalizability.