The U.S. fertility rate hit a record low in 2020 — just as it did in 2019, and 2018. Although the COVID-19 pandemic seems to have accelerated this decline, the drop has been underway for years. The total fertility rate — the average number of children a woman is expected to have over her lifetime — now sits at 1.64 children per woman in the U.S. Not only is this the lowest rate recorded since the government began tracking these stats in the 1930s, but it’s well below the so-called “replacement-level fertility” of about 2.1.

The latter number is what social scientists and policymakers have long regarded as the rate a country should maintain to keep population numbers stable. When the fertility rate falls below replacement level, the population grows older and shrinks, which can slow economic growth and strain government budgets. Today’s babies are tomorrow’s workers and taxpayers: They’ll not only staff the hospitals and nursing homes we’ll use in old age but also sustain the economy by funding our pensions when we retire, paying the taxes that finance Social Security, Medicare, and many other government programs we’ll rely on, and buying the homes and stocks we invested in to build our savings.

But recently, some experts have questioned whether we ought to be so concerned about low fertility. “There’s nothing really magical about replacement-level fertility,” said Erich Striessnig, a professor of demography and sustainable development at the University of Vienna. There are ways to overcome the challenges of low fertility, but it’ll take an investment in the people who have been born already.

The concept of replacement-level fertility goes back to at least 1929. At the time, birth rates in the U.S. and other industrialized countries had been falling for decades, and people didn’t know why. Attempting to explain this phenomenon, the American demographer Warren Thompson theorized that as these countries industrialized, people gained access to better medicine and sanitation as well as safer drinking water, leading to a sharp drop in death rates.

Read the full article about America's low birth rate by Stephanie H. Murray at FiveThirtyEight.