One need not be a fire-breathing social conservative to note that the American family is in some difficulties at the moment: Marriage rates have collapsed among the poor and the lower middle class, half of all children born to woman under 30 are born outside of marriage, and the American birth rate has dropped below replacement level at a time when we need all the younger workers we can get.
Mr. Eberstadt points out that this is true not only of one-child China, but also of the economically prospering Indian south, where fertility levels are at, or already below, replacement levels.
The low participation rate in the labour force by women, especially higher educated women, the alarming decline in the fertility rate below replacement level due to the delay in couples getting married, increase in singlehood, increase in couples not having children or having less, were cause for much concern.
By tackling such pregnancies, the fertility rate could be brought down to about 1.9 births per woman, slightly below replacement level yet high enough to ease concerns about economic stagnation and support for the elderly, said John Bongaarts, a demographer with the Population Council, a research group in New York.
From fertility that is almost as high as one can get to below replacement level in 22 years: social change can hardly happen faster.
In fact, the pattern was set back in the mid-1960s when the number of births fell below replacement level and life expectancy started to shrink.
Thailand's fertility rate decreased to below replacement level in the mid-90s.
The fertility level in most developing countries is expected to fall below replacement level.
With Cuba's birth rate having fallen below replacement level as far back as 1980 (partly thanks to Cuban women's universal access to reproductive health and abortions), and its work force shrinking, the country's vaunted health system faces pressing concerns about how it will care for the huge number of citizens readying to retire.
The TFR in 2011 ranged from 1.5 in Addis Ababa (below replacement level) and 4.0 in the Gambela region to 7.1 in the Somali region, while the national average was 4.8.
