Male Pattern Baldness
One interesting theory on why there is such a large percentage of male pattern baldness, advanced by Muscarella and Cunningham, suggests baldness came about in males through sexual selection as an enhanced signal of aging and social maturity, whereby aggression and risk-taking decrease and nurturing behaviors increase. This may have conveyed a male with enhanced social status but reduced physical threat, which could enhance his ability to secure reproductive partners and raise offspring to adulthood.
Male pattern Baldness Helpful Links:
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002160/ http://en.wikipedia.org/wiki/Androgenic_alopecia http://www.nlm.nih.gov/medlineplus/ency/article/001177.htm