why is my friend so hairy?

Answer 1

Could be due to a number of causes depending on how much hair it is, where it is and whether wanted or not. Possible causes are several and range from the amount of androgens (primarily testosterone and its derivatives) to even a condition called.Hypertrichosis which is the medical term for excessive hair growth and is most often considered a variation from the normal, primarily resulting from genetic factors.
http://en.wikipedia.org/wiki/Hypertrichosis

Answer 2

Hariness is mostly genetic and can be a sign of high levels of male hormones. Some women (like me) think hairy men are the sexiest!