Randy MacDonald has dropped a line pointing to an excellent and well-researched post on the demographics of Islam in France. You can read it at his livejournal site. In particular, he does something interesting in this debate – actually goes to INSEE (the French census and statistics office) and gets figures. I note particularly the following:

If [the French Muslim] population grew for the next 50 years at a rate of 2% per annum (a high rate, and one that doesn’t seem to be supported by signs of an ongoing demographic transition), while the remainder of the population shrunk at a rate of 0.5% per annum (also a high rate of decrease, and one that doesn’t seem likely to be achieved for a while given generally high French fertility rates), at the end of this 50 year period the total French population would have shrunk by 9%, and France’s Muslim population would amount to roughly one-fifth of the total. You’d have to wait for a century to approach a position of parity between the two populations, assuming the same unrealistic growth rates. This is definitely not any sort of imminent threat […]

[Translated from an INSEE report in French] As in 1990, foreigners living in France in 1999 have on average three children. The Spanish and Italians have fewer children than Frenchwoman, and Africans remain the most fertile. The older the immigration, the closer the behaviour of the foreigners is close to that of Frenchwomen. Like the French, the foreigners become mothers later than before. The schedule of births of Algerians and Moroccans, already close to that of Frenchwomen, has changed little. That of Tunisians approaches that of Frenchwomen. […]

French Muslims can, in theory, respond to the erosion of their ancestral cultures by trying to create a self-consciously “French” Muslim culture, trying to counterbalance the need for religious solidarity and respect for tradition with the need to deal with French culture. Indeed, the French government’s promotion of community religious organizations is part of an effort to construct just such a community. Still, building a culture from scratch is always more costly than assimilating into a culture that already exists and pervades your lives, like that of mainstream France.

By all accounts, they respond enthusiastically to opportunities of assimilation. INED’s fascinating statistics on language dynamics in France demonstrate, for instance, that most speakers of Arabic and Berber don’t pass on their languages to their children. The rising generation’s lack of native fluency in languages other than French isn’t a bar to communication with the wider Muslim world, given la francophonie and the possibility that Arabic might be learned by these French Muslims as adults. Language, though, is something critically important to the retention of ethnic identity; indeed, Islam places the highest importance on Muslim believers learning Arabic, so that they can understand the sacred texts of Islam.

Randy goes on to point out that the so-called threat of Islamisation is even weaker in the rest of Europe. I recommend going and reading the whole thing.

My only point of difference is that I think the French Muslim community is likely to sustain itself as a constructed French Islam, one with fewer elements of an ethnic identity and more along the lines of France’s other minority religions. In modern France, someone who wants, for whatever reason, to be religious is only being barely more contrarian by choosing Islam instead of Catholicism. Thus, I expect to see children and grandchildren of mixed-background homes adopting Islam. I think that one of the things that is different about the 21st century is that while Randy is right to highlight the cost of building new cultural frameworks rather than assimilating, I think the costs are far smaller than they were a generation ago.