When Europeans hear the words “America”, “religion” and “family values”, they think of brimstone preachers raging against unconventional domestic arrangements. They often forget the more positive role American churches play in nurturing conventional families.

What is striking, though, is the gulf between the fertility rate in the United States and other rich countries.

The fertility rate in Italy and Spain is [such that] without immigration, the number of Spaniards and Italians would halve in 42 years.

Can America cope with a relentlessly expanding population?

Whereas in the EU by 2050 there will be fewer than two adults of working age for every person over 65, the proportion in America will be less scary, at almost three to one. The problems of growth, says Mr Klineberg, are easier to deal with than the problems of decline.

If demography is destiny, [the world] will not have to find out what a Chinese hyperpower looks like: the fertility rate in China is only 1.7, and there are almost no immigrants.