The drop has accelerated the general trend towards lower fertility rates, especially in developed countries. Japan’s famously low fertility rate is less markedly different now than it was 20 years ago. In Germany, the U.S., U.K. and France the total fertility rate—the number of children an average woman will have in her lifetime—is now below two, and not expected to rise. Japan’s rate fell to 1.36 in 2019.

Previous examples of natural disasters and pandemics reducing the birthrate, like the Spanish Flu, preceded the widespread use of contraception. Education levels and other social factors like the average age of new parents were wildly different to today’s, so direct comparisons are difficult to make.

In some more recent examples like that of SARS in Hong Kong, fertility slumped during the epidemic before rebounding to above pre-pandemic levels. But that was a brief and limited episode compared with this one. Recessions tend to reduce fertility too. In the aftermath of the global financial crisis and euro crisis, one study found that falling birthrates were strongly related to increases in unemployment, affecting the worst-hit European countries most severely.