Have you ever been to Scandinavia? If not, maybe consider to visit it would proof you wrong. Secular educated societies always have a smaller birth rate, but not all of them are created equal. Family friendly, social societies with humanist values at heart are simply a better environment to have kids in than religious, family-hostile, anti-humanist and/or anti-social societies.
Maybe this is why some hardcore fundamentalists are against birth control? Because deep down they inherently recognize that given a free choice nobody would like to have kids in their dream world?
One cannot on the one hand claim to be for "family values" and on the other hand take every political decision that makes it harder to plan a family: social security, health care, liveable wages, state paid day-care centers, birth control — these are all things that increase the number of families being created, yet coincidentally they are all things a significant number of (american) christians hate.