CORE DP 2026 / 19

Fertility, Opportunity, and Intergenerational Mobility / Andreu Arenas, Jean Hindriks 

> Can demographic change affect intergenerational mobility even when fertility declines uniformly across communities? We show that it can when opportunities are unequal. We embed a quantity–quality fertility trade-off in a model of unequal opportunity. Under equal opportunity, fertility affects aggregate human capital but not intergenerational persistence. Under unequal opportunity, by contrast, fertility decline increases the intergenerational elasticity of income by transforming fertility differences into differences in human-capital transmission across communities. The effect is amplified by community inequality and applies equally to changes in child-rearing costs and endogenous fertility gaps. A US calibration shows that the mechanism is uantitatively meaningful and strengthens sharply with community inequality.