Most babies are born with no hair no matter what sex they are! When a baby does have hair when it's born, it's sex doesn't have anything to do with the length of its hair.
My son was born with a full head of hair and my daughter was born with a small amount of hair. We aren't born with long hair either. Also gender has nothing to do with how much hair we're born with.
Gender has nothing to do with the amount of hair a baby has when it is first born .. Or for that matter anytime during a person's lifetime. Genetics determines EVERYTHING about hair colour, texture and length .. Period.
My daughter was born with a lot of silvery blonde hair, which is fairly unusual for blondes; but there were several boys in the nursery with very long and thick dark hair. I don't think the gender plays a part.