“…Some studies use twins to control for interpersonal differences in unobserved characteristics, for example, Amin and Behrman (2014) use a small sample of twins to find that an extra grade of schooling reduces the number of children by 0.14. Most studies in the literature identify the causal effect through natural experiments (e.g., Aaronson, Lange, and Mazumder 2014;Black, Devereux, and Salvanes 2008;Breierova and Duflo 2004;Clark, Geruso, and Royer 2014;Dinçer, Kaushal, and Grossman 2014;Lavy and Zablotsky 2015;León 2004;McCrary and Royer 2011;Monstad, Propper, and Salvanes 2008;Osili and Long 2008). These studies suggest a negative effect of female education on fertility, with the exception of Monstad, Propper, and Salvanes (2008), McCrary andRoyer (2011), andClark, Geruso, andRoyer (2014).…”