I don't know if male pattern baldness really uses the acronym 'MPB' I used it anyhow.
So in my anthropology class a student did a research asking the question if male pattern baldness was a sign of evolution. I was very curious to his findings as I have been losing my hair very drastically these past few months. My forehead is HUGE! Anyways, here is a sentence or two I copied from his post.
One theory, advanced by Muscarella and Cunningham, suggests baldness evolved in males through sexual selection as an enhanced signal of aging and social maturity, whereby aggression and risk-taking decrease and nurturing behaviours increase.(1) This may have conveyed a male with enhanced social status but reduced physical threat, which could enhance ability to secure reproductive partners and raise offspring to adulthood.