In this paper, I estimate the causal effect that an additional year of schooling for parents has on their children's education, by exploiting a compulsory schooling reform that was implemented in all West German states between 1946 and 1969. Although previous research indicates that the reform had no effect on earnings, I find that an additional year of schooling for women strongly affects the education of their sons. There is no effect for the other parent–child gender pairs. I investigate numerous channels that might mediate the positive effect of the education of mothers. Most importantly, I find that individuals with more schooling value their children's educational success as more important.