Ever year or so the Times likes to run a Chicken Little story, warning us of the impending demographic and youth time bomb. I’m willing to bet the tradition goes back several decades. The bomb, oddly enough, is still ticking.

What about Asia and Latin America, where previous demographic crises have been predicted?

Elsewhere in the developing world, in Asia and Latin America, fertility rates have fallen sharply in recent generations and now resemble those in the United States — just above two children per woman. That transformation was driven in each country by a mix of educational and employment opportunities for women, access to contraception, urbanization and an evolving middle class. Whether similar forces will defuse the population bomb in sub-Sarahan Africa is unclear.

Is the lesson we should draw that Africa is different?