Think about it this way:
There are norms that most people fall into. Girls are generally feminine, emotional, and frail. Men are generally masculine, tough, and strong. We have it hardwired into our brains by the time we reach the age of five by constant ,"No Tommy, don't play dolls with your sister. Go play Football with your older brother." and ,"Susan, go play house with Anne."
If we so much as deviate from these behaviour patterns, our peers will single it out, and tease you about it. I was classified as a bookworm for most of my highschool career, until I decided to step out on the Rugby field. I dominated it through sheer willpower. Not because I was more athletic, but because I knew I could push myself harder than anyone else out there. I look back and laugh because I was considered a nerd that could kick your ass. Still makes me laugh. :P
Anyways, back on track...
We never had the opportunity to learn how to deal with our emotions. Girls were taught to express them, because that is how their mothers were taught. Our fathers taught us how to be strong, brave, etc.
It is one of the reasons why being a homosexual is "wierd" because that is not what we were taught to be. We were taught men and women should be together, not men/men or women/women. But that is going onto a totally different topic. :P Hope this helps! :)