Fertility in “post-demographic transition” countries

The extremely low fertility levels observed in some countries are the culmination of the process of social change that started with the demographic transition a few hundred years ago. This article argues that, as in the transition itself, the behavior of fertility today is closely related to changes in mortality. We briefly discuss the history of human population, and analyze the recent behavior of mortality and fertility across countries, in order to show that these two variables have remained intimately linked throughout the recent demographic history. We then argue that both economic and evolutionary theories suggest that this should indeed be the case: individuals should respond to reductions in mortality rates by reducing the optimal size of families. Only by understanding the determinants of the current behavior of fertility researchers and policy makers will be able to forecast its future trend and design adequate policies to deal with the problems at hand.