Returns to Birthweight

We use data on monozygotic twins to obtain improved estimates of the effect of intrauterine nutrient intake on adult health and earnings and thus to evaluate the efficacy of programs aimed at increasing birthweight. We use the results to evaluate the bias in cross-sectional estimates and to assess the proposition that health conditions play a major role in determining the world distribution of income. We show that there is considerable variation in the incidence of low birthweight across countries, and our estimates suggest that there are real payoffs to increasing body weight at birth. Increasing birthweight increases adult schooling attainment and adult height for babies at most levels of birthweight, but…