The fact that more boy babies are born during wartime makes perfect sense to those among us who believe in God - while those who put their faith in science are left wondering WHY? Be that as it may, this discovery was made in 1942 by the statisticians at the Metropolitan Life Insurance Company who collected the birth ratio data from the previous eighty years. Their discovery was immediately seen as big news by numerous magazines and newspapers at the time; the October fifth issue of Time Magazine wrote:
"In peacetime about 105 boys are born for every 100 girls. During and just after wars the ratio mysteriously increases to about 108 boys for every 100 girls. For the first time in World War II, this phenomenon has appeared in several warring nations of Europe, according to reports from Sweden last fortnight."
Even to this day it remains a hot topic and there is a great deal of HTML devoted to it.
Marriage vows were one of the unsung casualties of the Second World War: by 1944 many married women who hadn't seen their drafted husbands in years began producing babies; you can read about that here...