But, can't we make a distinction between culture and population. The scenario only points to a declining birth rates among the population. The culture and its institutions are still in tact, which are engines of enculturation. Those, who are immigrating may be resistant, but after each successive generation of the emigrant they become more like the new culture and less like the old. Every year about 6000 Muslims convert to Christianity and thousands more to a kind of secular deism. I'm not so certain Islam will dominate the future. Every time in history that they dominated, they soon went into decline with Sunnis and Shiites fighting each other. We shouldn't fear them, but do our homework, engage them and refute the errors of their false religion. Islam can't hold its own in a debate, because it built on falsehoods.