A: Well, some women do grow facial hair. This is usually caused by a hormonal imbalance, and is called hirsutism. Facial hair growth is mostly a by-product of male hormones called androgens, which includes testosterone.
Hirsutism is caused by a variety of factors such as adrenal- cancer or tumors, Cushing disease, congenital adrenal hyperplasia etc. It can also be caused by taking medication such as Cyclosporine, testosterone, anabolic
steroids etc. You will often see women who use steroids to hasten and amplify the effects of body building struggle with excessive facial and body hair, deep voices and so forth.
There are different theories as to why exactly a man usually has more facial hair and body hair (beard, moustache, thicker eyebrows etc) in contrast to a womanís mostly hair-free face, chest and back.
The theory that makes most sense to me is that in historic
times when man had to hunt for food and fight off wild animals, it was the male who went on the hunts while the women stayed in the cave or hut to look after the babies and cook and clean. Thus the male had to look bigger,
more fierce and dangerous as a scare-tactic to ward off wild animals and other unwanted or dangerous creatures.
Much the same as some moths have patterns on their wings that look like giant eyes to scare off predators. The
extra hair on their bodies also served to keep them warmer when they were on hunts etc...