Late or later? A sibling analysis of the effect of maternal age on children's schooling

Many studies have found that children born to young mothers face handicaps in their educational career. Considerable debate exists as to whether these effects are real age effects, or whether they are due to measured and unmeasured family background effects that are correlated with having children at a young age. In this study, we examine this problem by comparing siblings who were born at different ages of their mother. When effects of maternal age remain in sibling comparisons, they can be attributed to characteristics that change with the age of the parents and hence, they are more directly supportive of a possible causal effect of parental age. We also analyze the effect of mother's age in combination with the possible confounding influence of birth order: Children born at late ages on average are born later in the sibling row. Using data on 11,742 siblings in the Netherlands born between 1918 and 1974, our multilevel regression models show that there is a significant positive effect of maternal age on children's schooling and a small negative effect of birth order.