Abstract: Fertility has a strong biological component generally ignored by economists. Using the UK Biobank, we analyze the extent to which genes, proxied by polygenic scores, and the environment, proxied by early exposure to the contraceptive pill diffusion, affect age at first sexual intercourse, age at first birth, completed family size, and childlessness. Both genes and environment exert substantial influences on all outcomes. The anticipation of sexual debut and the postponement of motherhood led by the diffusion of the pill are magnified by gene-environment interactions, while the decline in family size and the rise in childlessness associated with female emancipation are attenuated by gene-environment effects. The nature-nurture interplay becomes stronger in more egalitarian environments that empower women, allowing genes to express themselves more fully. These conclusions are confirmed by heterogeneous effects across the distributions of genetic susceptibilities and exposure to environmental risks, sister fixed effects models, mother-daughter comparisons, and counterfactual simulations.
A new working paper has been added to the CINCH working paper series: "Maternal Age and Infant Health" by Cristina Borra, Libertad González, and David Patiño.
Abstract: We study the effects of maternal age on infant health. Age at birth has been increasing for the past several decades in many countries, and correlations show that health at birth is worse for children born to older mothers. In order to identify causal effects, we exploit school entry cutoffs and the empirical finding that women who are older for their cohort in school tend to give birth later. In Spain, children born in December start school a year earlier than those born the following January, despite being essentially the same age. We show that as a result, January-born women finish school later and are (several months) older when they marry and when they have their first child. We find no effect on educational attainment. We then compare the health at birth of the children of women born in January versus the previous December, using administrative, population-level data, and following a regression discontinuity design. We find small and insignificant effects on average weight at birth, but the children of January-born mothers are more likely to have very low birthweight. We interpret our results as suggestive of a causal effect of maternal age on infant health, concentrated in the left tail of the birthweight distribution, with older mothers more likely to give birth to (very) premature babies.
Abstract: This paper analyzes the long-term effects on mortality and socio-economic outcomes from institutional delivery. We exploit two Swedish interventions that affected the costs of hospital deliveries and the supply of maternity wards during the 1926–46 period. Using exogenous variation in the supply of maternity wards to instrument the likelihood of institutional delivery, we find that delivery in hospital has substantial effects on later-life outcomes such as education and mortality. We argue that a decrease in child morbidity due to better treatment of complications is a likely mechanism. This interpretation is corroborated by evidence from primary school performance, showing a large reduction in the probability of low performance. In contrast to an immediate and large take-up in hospital deliveries as response to an increase in the supply, we find no increase in hospital births from the abolishment of fees – but some degree of displacement of high-SES parents.
