The Eclectic Econoclast has a post about the declining birth rate in Iran, which is apparently of a magnitude similar to places like Japan where talk is of an aging society.
The primary tools for bringing about this change have included greatly increased support for family planning, subsidized condoms and other contraceptives or vasectomies, and reduced bonus payments for larger families.
I was struck by the subsidzed condoms, etc. in a theocracy. I will grant that I have an incomplete knowledge of Islam, but I had always been struck by the similarities with Judaism and Christianity on many social issues. I’m somewhat surprised that the Prophet didn’t record a command to “go forth and multiply.”