Fertility and Wars: the case of world war I in France

During World War I (1914–1918) the birth rate in France fell by 50%. The corresponding deficit of births is estimated at 1.4 million, while military losses are estimated at 1.4 million too. Thus, the fertility decline doubled the demographic impact of the war. I construct a model of fertility choices where a household faces three shocks in a war: (i) an increased probability that its wife remains alone after the war; (ii) a partially-compensated loss of its husband’s income; and (iii) a decline in labor productivity followed by faster growth. I calibrate the model’s parameters to the time series of fertility before the war. I use military casualties and income data to calibrate the war. The model accounts for 91% of the observed decline, and overpredicts the subsequent rebound in fertility by 4%. The increased probability of a husband dying is the leading force behind the results