Doug–I’d be interested to know where you got that information (re Mexican birthrates in the US). I am a volunteer physician in a clinic that serves working immigrants, overwhelmingly Mexican, and we have a large obstetrical practice. In talking with the young mothers who come there they virtually all mention that they plan to have a smaller family than their mothers had in Mexico. Among several things, children are more expensive here and their moms often didn’t have access to, or knowledge of, contraception.

It may be that the most recent arrivals continue for a while to have big families but it’s a universal tenet of demographics that the desire for large families disappears after moving to a more-developed economy. As Stengel said, “You could look it up.”