The diverging destinies hypothesis predicts that educational inequality increases in contemporary societies because parents with higher levels of education postpone the birth of their children. This hypothesis is supported by empirical evidence demonstrating that advanced parental ages improve children’s educational outcomes. However, the consequences of socioeconomic differences in parental ages for the intergenerational transmission of education also depend on whether the associations between parental ages and child education vary by parental education. To test this hypothesis, we use data from three countries representing different welfare regimes: Germany, Norway, and the United States. In all three countries, children’s educational attainment at the secondary school level increases with higher parental ages more in families with low than in families with highly educated parents. In other words, the intergenerational transmission of education is stronger for younger than for older parents. Consequently, our findings nuance the diverging destinies hypothesis by demonstrating that increasing parental ages in socioeconomically disadvantaged families increases educational mobility more than decreasing parental ages in socioeconomically advantaged families. These findings are qualitatively the same in all three countries, suggesting that diverging destinies also occur in countries outside the United States.