I kind of am interested in the theory that the greys aren't aliens, they're time travelers from the future. They have big heads and tiny bodies but are humanoid. If you predict human evolution that would happen because we don't need to be as physical and we'll have robots doing the physical labor and intelligence will be more important. You already see how humans are babies longer than other mammals because our big heads make it harder to more around and women's birth canals get stretched during pregnancy because babies have such big heads. The only problem is in the meantime the world still values a masculine man, that is what women are attracted to, so the more intelligent less masculine man are less likely to breed and continue their line. This is why guys give up and go there own way and become incels.