That is a good point, which I accept, Scott-wot. I just saw this explanation mentioned once, which is not my gold or silver standard.

That said, Vitamin D is absorbed better when the sun is less strong and the skin has less pigmentation. Vitamin D is of course healthy both for the mother and the fetus. In northern latitudes, a fetus benefits therefore from a mother with lighter skin tones, while in tropical areas the fetus is protected better (and the mother as well) when the mother has darker skin tones.

Thank you for an excellent reply.