A Popular Explanation for Low Birth Rates Has a Big Problem

Society is running out of babies, and no one can agree on why. Most people around the world, including Americans, live in a country where overall fertility is below what demographers call the “replacement rate,” meaning that without migration, the population will shrink from one generation to the next. In some places, the birth rate is so low that each generation is set to be half the size of the previous one. A number of theories have been put forward to explain why this is happening. Some…