This article introduces a framework to study parental investments in the presence of birth order preferences and/or human capital cost differentials across children. The framework yields canonical models as special cases and delivers sharp testable predictions concerning how parental investments respond to an exogenous change in family size in the presence of birth order effects. These predictions characterize a generalized quantity–quality trade-off. Danish administrative data confirm our theory’s predictions. We find that for any given parity, the human capital profile of children in smaller families dominates that of large families, and that the average child’s education decreases as family size increases, even after taking birth order effects into consideration.
