Stillbirth and Caesarean Section as Natural Experiments to Identify the Causal Effect of Family Size on IQ and Educational Attainment

This paper proposes stillbirth and caesarean section as natural experiments to identity the causal effect of family size on children’s IQ and educational attainment. Stillbirth is hypothesized to affect family size by shortening the intervals between subsequent births and thereby making a higher total fertility more likely. Caesarean section is hypothesized to lower total fertility by decreasing fecundity. I use data from the British National Child Development Study to estimate the causal effect of family size on various measures of IQ at age 7, 11, and 16 and completed years of schooling at age 33. OLS estimates show that family size has a negative effect on all IQ measures and completed years of schooling. However, 2SLS models which use stillbirth and caesarean section as instruments for family size show no causal effect of family size on IQ and educational attainment.