I will say this about the boys and school thing: At my friends’ daughter’s school, a popular game is “See who can be quiet longest.” I assume this is a game promoted by the teachers, since I can’t imagine children coming up with it.
Anywho, if what’s prized most in school is sitting still and being quiet, it’s easy how a proclivity for running, climbing, exploring, breaking things, and wrestling with your friends could wind up getting you labelled as a problem.