Comment on Are more male babies born after wars?
Just a wild-ass theory I thought of. I think we can safely assume that if there is a gender bias among babies, it must be a genetic trait. And I think it’s easily arguable that some of the traits we’d associate with being a soldier have some genetic basis. For example, people with bad eyesight or flat feet or asthma don’t get drafted to serve.
Now suppose these “non-warrior” genes are associated with a “male-baby-preference” gene. What happens when a big war starts? The men with warrior genes get selected to go off to fight (and maybe not return). The men with the non-warrior genes stay home - and these men have a genetic preference for fathering male babies. So the ratio of male babies being born increases.