Religious people have more children. Family formation has historically been much more affordable in the US than in Europe and Japan, and most of the rest of th

Religious people have more children. Family formation has historically been much more affordable in the US than in Europe and Japan, and most of the rest of the world. So desire and culture has been the primary constraint on an individual's choice to have one or another child, whereas in other places the constraints have been more financial. Religious people in the US out-breed non-religious people at a higher rate than is possible elsewhere. If you look at the demographics, blue state urban liberals will be an endangered species in a few decades. They barely have children. Compare Hillary's only child to Pallin's brood.