War is a time of hardship, sorrow, and separation. Yet, in its aftermath, there is a curious phenomenon that has baffled scientists, delighted historians, and added a few extra lines to the family trees: the Returning Soldier Effect. It is not just a heartwarming reunion story—it is a biological trend. After conflicts like World Wars I and II, many countries noticed an unusual surge in the number of boys born compared to the number of girls. But why? Carl Düsing, a German biologist in the late nineteenth century, put forth a theory to explain the strange phenomenon. Düsing’s idea, now called the “Returning Soldier Effect,” was his attempt to unravel why, after soldiers returned from wartime conflicts, societies seemed to produce more boys than girls.