The problem is that correlation is not causality. The same thing that makes people religious (holding on to an old reality/world view) is totally in character

The problem is that correlation is not causality. The same thing that makes people religious (holding on to an old reality/world view) is totally in character with having more children for the exact same reason. Also religious people are more likely to want to preserve the status quo at all costs, which includes obsolete family structures. The fact is most people are becoming secular by the day and most people are having less children. Sampling from the laggards means nothing. God is already dead. It just takes a while to get rid of the body.