World War I had big impact on populations
In the aftermath of World War I, the French population declined due to male soldiers’ deaths in the war.
Almost 1.4 million French soldiers lost their lives out of a population of just 19 million males. Thus, the birth rate declined and the population of France declined as well.
Consequently, the French government gave a medal to any woman who had 10 or more children, but that wasn't all. The woman got a monthly check from the French government; it wasn't a lot of money, but more of a token of appreciation. My wife is French and her grandmother had 11 children, so she was one of those honored and received her medal.
As most know, the war started in 1914 and ended in 1918, the year the United States entered the war. The United States had 58,000 killed in action.
Around 18,000 are buried in France at a cemetery at Romagne. I have visited this cemetery several times. I have also visited the World War II cemetery at Omaha Beach in Normandy.