jlokom
This sounds like a strawman. Many people don't want to have kids for different kinds of reasons (personal objectives, couple style of life, they don't like kids, etc). You seem to have a very low opinion of people that don't want to have kids and, on the other hand, a very high opinion of people that do have kids.
I see this quoted a lot, but I don't think it's true:
+ There are plenty of places (and with a significant population) outside the western world that are quite secular and have become more secular in the past decades + There are places in the West that have become more religious. If by "Western" you mean just "Western Europe", then, yeah, that's a specially secular place but it's also a tiny place in both population and area.
China, Japan and South Korea are quite secular in many ways. A big chunk of Latin America is now quite secular too. You already have ~1.5B people fairly secular people that are non western.
On the other hand, countries like Poland or Hungary (which I'm guessing we would classify as Western) are becoming more religious.