Oriental and native American races have far fewer follicles that develop coarse growth after puberty than for example Caucasians do - and a large number of African races also have less of these follicles. This results in orientals, etc. having much less evident stubble developing between shaves and, if growing a beard, a much thinner and less luxuriant overall than Caucasians. Not being an expert, I however think the amount of hair follicles is probably nevertheless similar on all races. As to why the follicles of non-Caucasian races are less likely to produce coarse hair, the reason is no doubt genetic - could one speculate that Caucasians developed this as a result of exposure to the cold ? Hardly, because Inuits are the ultimate cold area inhabitants and they have the same thin beard characteristic - ah, but then from a very early stage they possibly knew better how to protect themselves from the cold than did the Caucasians some of whom imagine they live in a tropical paradise and still keep their windows open in cold weather and are reluctant to use central heating to the full (or is that just miserliness).