The Baby Bust Generation

The Baby Bust Generation

FERTILITY IN AMERICA has been declining for years. According to the Pew Research Center, the nation's birth rate hit an all-time low in 2011 – just 63 births per 1,000 women of childbearing age. It was almost twice as high – 123 births per 1,000 women – at the peak of the Baby Boom in 1957.

As babies and children disappear from a society, what takes their place? One answer, as journalist Jonathan V. Last observes in a forthcoming book, "What to Expect When No One's Expecting," is pets.

In surveys taken from the 1940s to the 1980s, fewer...