Not based on what I've seen which puts the US at 2.09 where the neutral (population neither increases or decreases) replacement fertility rate is 2.1. Given that the "boomer" rate was 3.8 no way is 2.09 going to pay for the entitlements for the very much larger boomer generation.
I can't locate anything on birth rates broken down by religious groups but I do know that, at least in Europe, the Pope was issued alarms about the decline in birth rates among Catholics.
Europe is Europe.The lack of births among liberals is severe enough to bring down the national birthrate. There is a shift going on and as the believers increase in numbers the birthrate will turn restorative once again.