First of all the numbers are in question. The top google link on USA fertility says that US fertility is on the rise and is 2.1 as of 2006. That number could be interpreted in several ways, but the point is the US rate is not as stated by the clip. France is also listed as higher that the clip says.

Islam is as much threatened by the numbers as Western culture. A good example is Turkey which is a long time secular Islamic state filled with Muslims that are no more radical than your typical Methodist. The question is, what will the Muslims of 2050 resemble? Will they be secular Muslims or radical Muslims. History indicates the former. Immigrant Muslims are being constantly innoculated by the culture that they have immigrated to, and the results 40 years down the road is not easy to predict.

Radical belief can only thrive in an environment of hopelessness. The Russian brand of Communism was popular as long as Russians were starving. When their bellies were full, their thoughts turned to lipstick, Levis and walkmans.

I doubt it will go the way they predict. It could, but we could all perish from swine flu or a comet could end it all.

Technology is the great problem solver.