Spousal education is correlated with earnings for two reasons: cross‐productivity between couples and assortative mating. This article empirically disentangles the two effects by using Chinese twins data. We have two innovations: using twins data to control for the unobserved mating effect in our estimations and estimating both current and wedding‐time earnings equations. We find that both crossproductivity and mating are important in explaining the current earnings. Although the mating effect exists for both husbands and wives, the cross‐productivity effect mainly runs from Chinese husbands to wives. Our findings shed light on the theories of human capital, marriage, and the family.

This study investigates the effects of unobserved earnings-related endowments on marital outcomes, focusing on potential gender differences. Using a less stringent, more plausible assumption that monozygotic twins share more similar endowments relative to dizygotic twins, we develop a novel identification strategy from the twins experiment. Using unique Chinese twins survey data, we find that men with genetic endowments related to higher earnings marry earlier and have younger, taller wives; such women marry later and have older husbands with higher education and income. Results cast doubt on the conventional assumption of independence between unobservables and observable marital attributes.