Baby busts and baby booms

"Economic demographers have long analyzed fertility cycles. This paper builds a foundation for these cycles in a model of fertility choice with dynastic altruism and aggregate shocks. It is shown that under reasonable parameter values, fertility is pro-cyclical and that, following a shock, fertility continues to cycle endogenously as subsequent cohorts enter retirement. Quantitatively, in the model, the Great Depression generates a large baby bust -- between 38% and 63% of that seen in the U.S. in the 1930s -- which is subsequently followed by a baby boom -- between 53% and 92% of that seen in the U.S. in the 1950s"--National Bureau of Economic Research web site.