Since this is a very politicized topic, as a Muslim I feel it is worth pointing out that there is nothing in Islam that promotes having many children per se (this topic is even omitted in the linked Wikipedia article).
On the contrary, Islam does not forbid contraception or even abortion, up until four months of gestation.
Works for all those conservative states! My wife's from Louisiana and she can count on one hand the number of female schoolmates who made it out of high school, let alone to 21, without a child.
https://en.m.wikipedia.org/wiki/Muslim_population_growth