I've noticed a lot of people on this forum are from northern countries (ireland, norway, sweeden, even germany, denmark or so ). It seems these people have inherited very sensitive receptors, given that their lab tests usually show they have normal DHT levels, and they don't even have body hair or other typical signs of elevated androgen levels.
That certainly shows that some nations and phenotypes (ginger and blonde hair - In the same time I admit male pattern baldness genes are not directly linked to hair color or texture) are more prone to the onset of male pattern baldness regarding their genetic pool. Many people here with aggressive Androgenetic Alopecia have blonde hair, like FredTheBelgian and other members.
Maybe those nations are genetically more linked to Neanderthal genotype, as xredstar already said, that would explain why there is a greater prevalence of baldness in Caucasian population especially the one living in northern Europe. I've been in England, and was surprised how much there were young balding guys on the street (between ages 20 to 30) with receded hairline or thinning hair on front or crown. And I haven't noticed hair loss issue looking at guys which obviously had origins from India, Afghanistan, or middle east .
Is there any evaluational reason and factor why Neanderthals developed balding genes. Maybe certain effects of environment, like lack of sun exposure can also have some link to it ?