From one of my favorite bloggers, Tyler Cowen… (you should read his the whole post)
Part of the demographic problem, of course, is that the real standard of living in Western Europe is remarkably high. Western European women have learned how much fun they can have, living in Europe and traveling abroad, when they are not tied down with four children. The extreme secularism of Western Europe Ã¢â‚¬â€œ a philosophy which I share and indeed cherish Ã¢â‚¬â€œ also promotes small families. Religious exhortations to have more children, combined with a child-friendly church culture, do in fact raise birth rates. In both economic and cultural terms, Western Europe is not investing enough in its future.
It seems that for Western Europe to regain its dynamism, it has to move to a freer market economy, higher rates of childbirth, higher immigration, and greater religiosity. It has to stop being the Europe which we (or at least I) love, and become more like the United States.