Of all the controversial mammalian features of Homo Sapiens, hair is perhaps the oddest.
We love it long on a woman's head. But heaven forbid she should ever have any hair on any other part of her body except her eyebrows. Millions of dollars are spent every year on various painful ways to pretend that the female body is hairless below the aforementioned eyebrow line.
Nature gave men beards. But modern men for the most part have rejected them, and cut and scrape the growth every day. Then again, you have certain religions that demand their men grow beards -- even the Old Testament gets into the debate.
Men feel virile with hairy chests and thick head hair. But the very hormone that got the stuff going, is what takes it away later, at least on the scalp. At about the same time, it sprouts in embarrassing places, such as the nose, ears and back.
And then, what's left turns grey.