Why do girls usually have long hair?

i thin it just because for the fashion. or the girl under control of her boy friend which one he like his girlfriend have long hair. and long hair make a simple initialitation of gender. who decided that pink was for girl and blue was for guys is?? absolutely it is not me:))

Who said that a woman must have long hair and a man must have a short hair?? and who said pink are for girls and blue are for boys???
I think if we take a look in common life, we can see those thing but we can't generate it to all people. What about male rocker with long hair? he is a male right? but why has long hair? I think it's depend to people's choice towards to their life style or their convenience.
I am a woman but honestly I don't like pink, too shiny for me lol, and I think there's so many woman don't like pink and maybe they like blue.
But yeah, maybe pink are sweet color so that this color related to a girl. And blue are cool color and it match with a boy, not a man:P