War and the secondary sex ratio: Are they related?

Abstract

This study sought to verify reports of increasing proportions of males being born during times of war. We analyzed the sex ratio of over 12,000 births occurring between 1940 and 1980, over 9000 of which occurred specifically in the United States, with the remainder taking place primarily in Canada, Our findings confirmed that, for both the United States and elsewhere, significantly greater proportions of males were born during times of war than during years of relative peace.