Why do these Muslims breed so Fast?

Why do the Muslims(Gentile non believers) breed and grow so fast? Why do our People, Americans and Israelis, reproduce so slowly, why are our people so impotent, is it that we are impotent?? In Church i know we are taught is bad, and Jews(half Gentile) know this, just as they know the way of CHRIST is the right path. So why dont we grow like them? How is the prophecy to come about if we don't grow?