The effects of birth weight: Does fetal origin really matter for long-run outcomes?

This paper investigates whether birth weight itself causes individuals' future life chances. By using a sample of twins in Japan and controlling for the potential effects of genes and family backgrounds, we examine the effect of birth weight on later educational and economic outcomes. The most important finding is that birth weight has a causal effect on academic achievement around the age of 15, but not on the highest years of schooling and earnings.