Finding workers willing to do low-wage housework is challenging in Japan, given widespread labor shortages and restrictive immigration policies. But again, bit by bit, the government has been trying to change that. In fact, this month the Japanese parliament passed controversial legislation allowing more immigration, in part to address precisely this issue.

In a sense, then, Japan has learned the opposite lesson of the United States: If you want more babies, find ways to make it easier for working people to have kids — through both more family-friendly workplace policies and a more liberal immigration system. (Immigrants, by the way, tend to have more babies than do native-born Americans.)

And preferably, do all this before the demographic time bomb explodes.