this is mostly from a very old smithsonian article. i have that one handy in my bookmarks. that and the one that explains why 'men can't cry' as much women(due to differences in prolactin and men having larger tear glands that prevents tears from 'spilling out'). recently, there has been a rash of mad moms encouraging their sons to cry like in some kind of bizarre social experiment when the poor dears are not biologically built to turn on the waterworks like we can.