Mmmm, but in the Arab Muslim world the birth rate is completely unsustainable and must collapse in the near future. The demographic numbers I have seen show Islam's relative position in the world unchanged for the next 40 years. The mid-east in particular in sitting in a demographic time bomb that must change, the economies of the region are not capable of supporting the coming bulge of 15-24 year olds. Either people will choose smaller families on their own, or else they will have no choice due to economic and resource limitations.