You are more likely to have children if you are a follower of a religion than if you are not. Not just because you are more likely to have sex, but because you will be doing so with people more likely to be fertile. A church is probably not the best place to go for a one-night stand, but if you want to meet people who are ready, willing and able to get married and go forth and multiply, they are veritable hot-beds of lust and seething passion.
This is not just something I have made up off the top of my head in order to attract traffic to this website – it is the finding of some academic from Cambridge. Ironically, I find that he is a Professor not of Religion, Genetics or Fertility but of Economics. Presumably the world-wide recession has quietened down for the moment, leaving him with time on his hands! More seriously though, because Religious people allegedly have more children than non-believers, then this means that there will be a natural tendency for the number of people following a religion to increase in proportion to those that do not.
The great irony of course is that religion may be a meme, but so is the idea of criticising overpopulation – with one crucial difference: the former by its very nature encourages its own continuance, whilst the latter is actually encouraging its own extinction. Oh how Richard Dawkins must be kicking himself!