Actually if there are consistently 10% migratants with a fertility rate above the average, this will cause a growth in whatever ethnic groups are migrating - ev

Actually if there are consistently 10% migratants with a fertility rate above the average, this will cause a growth in whatever ethnic groups are migrating - even if you just consider them 'french' or 'spanish' in the second or third generations. Muslims make up 8.8% of France right now, and they have grown significantly as a percentage of the population even in the last ten years almost a percentage point. Will this ever go to 50%? Probably not but we are likely to see a higher fraction in the future.