The magic fertility number, if you want the population to remain stable, is 2.1 children per woman. Today, the U.S. fertility rate perches at 2.01. Compared to countries like Poland (1.32), Germany (1.36), and Singapore (1.11), that might seem impressive. But as Last points out in What to Expect, America’s buoyant fertility may be a statistical mirage.

Break the numbers down demographically, and the trends seem less promising. For college-educated women, for instance, the fertility rate is roughly 1.6. As education goes up, fertility shrinks. Hispanic women, meanwhile, pull far more than their own weight, with an average rate of 2.73. The problem? Their fertility numbers are falling fast as well, and continue to plummet as immigrant women assimilate into the larger U.S. culture…

The best arguments for having children, unfortunately, run opposed to modern, secular American culture. Good reasons to have kids tend to be about delayed gratification, prioritizing family, putting others first, transmitting serious values and beliefs, focusing on something larger than yourself, and understanding the difference between joy and fun. Perhaps this is why, as Last notes, “American pets now outnumber American children by more than four to one.” It’s also why, if American fertility continues to slide — and, as the author notes, that’s still an “if” at this point — there’s little the government can do.