The Story: A new report by the Census Bureau finds that the population of the United States grew at the lowest rate since the nation’s founding. How will that affect the church in America?

The Background: Between July 1, 2020 and July 1, 2021, the population of the U.S. grew by 392,665, or 0.1 percent, according to a recently released Census report.

Populations can change—increase or decrease—through three processes: fertility (the number of children that women have), mortality (the number of deaths that occur), and migration (the movement of persons from a locality of origin to a destination place across some predefined, political boundary). The record low rate is due to both decreased fertility and migration, and an increase in mortality. 

“Population growth has been slowing for years because of lower birth rates and decreasing net international migration, all while mortality rates are rising due to the aging of the nation’s population,” said Kristie Wilder, a demographer in the Population Division at the Census Bureau. “Now, with the impact of the COVID-19 pandemic, this combination has resulted in a historically slow pace of growth.”

The record low rate is due to both decreased fertility and migration, and an increase in mortality. 

The growth during this period was due to natural increase (an additional 148,043 people)—which is the number of excess births over deaths—and net international migration (244,622 people). This is the first time that net international migration (the difference between the number of people moving into and out of the country) has exceeded natural increase for a given year.

What It Means: The first command given by God to mankind was to “Be fruitful and multiply” (Gen. 1:28). The command is repeated when God makes a covenant with Noah and his family (Gen. 9:1). But what happens when a nation not only stops multiplying but starts decreasing?

The level of fertility (i.e., the actual production of offspring) at which a population exactly replaces itself from one generation to the next is known as replacement-level fertility. In developed countries, such as the U.S., replacement-level fertility requires an average of 2.1 children per woman. This means 100 women will bear 211 children, 103 of which will be females. (About 3 percent of alive female infants are expected to die before they bear children, thus producing 100 women in the next generation.)  

Fertility rates began falling in Western, industrialized countries in 1968 (oral contraceptives, first introduced in 1960, had become widely used by then). By 1975, every Western First World nation was below the replacement rate. The current fertility rate for the U.S. in 2021 is 1.781 births per woman. 

Sub-replacement-level fertility rates can have a wide-ranging effect on everything from marriage to sex trafficking to global conflict. This is why Western countries push to replace their pool of working-age people through immigration. The United States, for instance, has more immigrants than any other country in the world. Our foreign-born population reached a record 44.8 million in 2018. Immigrants today account for 13.7 percent of the population, nearly triple the share (4.8 percent) in 1970. 

But increasing immigration levels is not popular. A Gallup poll taken in July 2021 finds that only one-third of American adults (33 percent) want to increase immigration, while another third wants it to decrease (31 percent), and an additional third (35 percent) want to keep levels the same. 

Even if the U.S. increases immigration, though, it won’t necessarily offset ​problem of declining fertility. As historian ​​Philip Jenkins says, this change has “epochal implications for all the world faiths, and especially for Christianity.” In an article for TGC published in June, Jenkins noted: “The [decline of fertility] foreshadows a precipitous decline in organized and institutional religion of all kinds, since fertility rates correlate so closely with religious practice and affiliation.”

“The accelerating demographic revolution subverts or renders irrelevant so many activities that religions have long been accustomed to see as essential to their existence and their work,” said Jenkins. “As those features fade, so religions of all kinds are forced to reconsider what their core purpose actually is; what is the heart of the matter. That exercise in rethinking could be prolonged and even painful, but the potential opportunities are rich indeed, and at a time of special human need.”