...economic's strength lies in testing perceptions against data...
In recent travels I encountered the claim that Muslims are aiming to overrun the rest of the world by ordering their women to open their wombs. The result, I was told, was that Muslim women average 8 children each, dooming the non-Muslim world to subjugation.
I was skeptical, because it goes against all the evidence from countries I study -- primarily the US, Japan and China -- about the behavior of women. Variation across the Islamic world is vast; strife in Iraq ought remind us these are not surface variations. So with several hundred million adherents someone, somewhere surely is advocating higher fertility as an Islamic duty.
But that doesn't mean that women are listening. China tries to restrict fertility to one child; despite draconian, indeed horrific measures to enforce it, fertility rates there remain above those of Japan and Korea. My hunch was that in their fertility countries that are heavily Muslim look little different from the rest of the world -- low and falling, particularly in prosperous countries.
Countries do collect this sort of data. Of course businesses want a good census to help in product planning, capacity planning and marketing. Fertility data are also valuable, necessary for governments to structure healthcare policy -- clinic construction, midwife training -- and budget for school construction. While data collection is a challenge in very poor countries, only a minuscule fraction of the world's population remain nomads.
So what do the data show? Egypt's fertility is below that of the Philippines; India's is above that of Bangladesh. The fertility rate of Indonesia, the world's most populous Islamic state, is at replacement level, as 2.1 children per mother are necessary to guarantee that on average at least one daughter will live to reproductive age. Radical Iran is below that level -- perhaps Americans don't realize that it is a literate and (relative to its neighbors) prosperous society.
Economists watch what people do, they don't rely on what they say. Men may talk the talk, if they're part of the increasingly unpopular ruling party. But words alone are impotent.
...words alone are impotent...
The real lesson is that fertility is falling across the world, no matter the religion, and that as incomes rise, fertility falls. Sub-saharan Africa remains anomalous, but if you want to look at the data – the World Bank has a nice web site for that -- you'll find that even there change is evident.