Fertility and Ethnic Diversity

This paper relates national fertility rates to political factors. I first review evidence that community norms affect fertility, ethnic groups compete politically in many countries, and a group’s relative size affects its ability to compete. This evidence jointly suggests that population growth and fertility may be public goods at the ethnic group level in diverse societies. Next, I present a simple model of ethnic conflict where a high fertility norm within each ethnic group emerges in a unique equilibrium if ethnic diversity is high and/or institutions are weak. In the opposite case, fertility is low. Finally, I test empirically for a link between ethnic diversity and fertility in a cross-national dataset and find a robust positive relationship. Consistent with more intense conflict where institutions are weaker, ethnic diversity’s effect on fertility decreases with income per capita. On the other hand, there is no evidence of a link between fertility and religious diversity.