War, Marriage Markets, and the Sex Ratio at Birth

Abstract

In belligerent countries, male-to-female sex ratios at birth increased during and shortly after the two world wars. These rises occurred amidst dramatically changed marriage-market conditions caused by war-related declines in adult sex ratios, and still defy explanation. Based on county-level census data for the German state of Bavaria in the years just before and immediately after World War II, we explore the reduced-form relationship between changes in marriage-market tightness (the adult sex ratio) and changes in the offspring sex ratio, and we discuss potential mechanisms that might link the two. Our results suggest that war-induced shortfalls of men significantly increased the percentage of boys among newborns.