The intergenerational effects of birth order on education

We study the intergenerational effect of birth order on educational attainment using rich data from different European countries included in the Survey of Health, Ageing and Retirement in Europe (SHARE). The survey allows us to link two or more generations in different countries. We use reduced-form models linking children’s education to parents’ education, controlling for a large number of characteristics measured at different points in time. We find that not only are parents who are themselves firstborns better educated, on average, but they also have more-educated children compared with laterborn parents (intergenerational effect). Results are stronger for mothers than for fathers, and for daughters than for sons. In terms of heterogeneous effects, we find that girls born to firstborn mothers have higher educational attainment than girls born to laterborn mothers. We do not find evidence for potential channels other than parental education that could explain the intergenerational effect of parental birth order.

Intergenerational effects of maternal birth season on offspring size in rural Gambia

Environmental conditions experienced in early life can influence an individual's growth and long-term health, and potentially also that of their offspring. However, such developmental effects on intergenerational outcomes have rarely been studied. Here we investigate intergenerational effects of early environment in humans using survey- and clinic-based data from rural Gambia, a population experiencing substantial seasonal stress that influences foetal growth and has long-term effects on first-generation survival. Using Fourier regression to model seasonality, we test whether (i) parental birth season has intergenerational consequences for offspring in utero growth (1982 neonates, born 1976–2009) and (ii) whether such effects have been reduced by improvements to population health in recent decades. Contrary to our predictions, we show effects of maternal birth season on offspring birth weight and head circumference only in recent maternal cohorts born after 1975. Offspring birth weight varied according to maternal birth season from 2.85 to 3.03 kg among women born during 1975–1984 and from 2.84 to 3.41 kg among those born after 1984, but the seasonality effect reversed between these cohorts. These results were not mediated by differences in maternal age or parity. Equivalent patterns were observed for offspring head circumference (statistically significant) and length (not significant), but not for ponderal index. No relationships were found between paternal birth season and offspring neonatal anthropometrics. Our results indicate that even in rural populations living under conditions of relative affluence, brief variation in environmental conditions during maternal early life may exert long-term intergenerational effects on offspring.