It seems that
religions are the same as any
organism. They
evolve the same way. The strongest survives and spreads, and continually changes to promote it's own existance.
For instance
Mormons were encouraged to have
multiple wives, and often had well over a dozen children. The more babies, the more followers of their
religion. I think that's part of
pro-life too, although as an order from higher up, not at the individual follower level.
Or certainly more appropriate, come to think of it, is religions which refuse the use of
contraceptives.
Sex is fun, there's really
no preventing it. So refuse
contraceptives for some dumb reason, and they're guaranteed to have a bunch of children.
Voi-la, the religion lives on.