OK, here are some facts about human hair: 

1) People who wear their hair long aren't less healthy or more likely to get sick
2) There is no known way to measure how long or short someone's hair should be
3) It's impossible to know in advance what hair styles will be in vogue in a decade or even a year
4) Men can wear long hair in any field or job, and no one will think it's odd
5) Hair style is primarily a matter of individual preference or cultural norms
6) This particular rule for young men is relatively new. Hair styles for men have varied for thousands of years in a way that has nothing to do with the male sex hormones.
7) There are many societies in which men grow out their hair and women grow theirs shorter.
8) The current rule is rooted in a misguided fear that is decades out of date, which no longer applies in this country.
assistant
Hmm, in our culture it seems like you’re not supposed to have long hair if you’re a boy. What is it about long hair that makes it a bad thing?
assistant
Why shouldn't boys have long hair?
user