The new economics of babymaking

A few miles south of Salt Lake City, deep in Utah County, the town of Payson is on parade. Toddlers run between trucks that tug floats carrying cheerleaders and footballers. Seven beauty queens wave from a giant watermelon; the next float bears 36 bagpipers. Every performer in this annual celebration is a child. All told, it takes them two hours to pour onto the streets.

Between 2008 and 2024, the fertility of America’s average woman fell by a quarter. The country’s population is ageing and, should birth rates stay low, will eventually shrink. But in Payson, unlike most towns, children still outnumber adults. More babies were born in Utah County in 2024 than a decade earlier. Although fertility has fallen faster than the American average in the wider state, the county makes more babies than almost anywhere else in America. In southern districts, according to the mayor’s office, the birth rate is twice the national average—and rising.

Economists modelling women’s choices have long assumed that falling birth rates are down to rising incomes. In a rich, meritocratic country, couples have reason to spend more on education and other ways to boost their offspring’s life-chances, leaving less to spend on additional babies. As more women join the labour force, the opportunity cost of having a child rises, since child-rearing time could instead be spent advancing a career. It is for these reasons, economists have tended to think, that rich women in America have fewer children than their poorer peers.

But recent research and birth trends have challenged this consensus. Within high-income countries, women in the richest places now have the most children, rather than the fewest. Birth rates among the poorest women are falling fastest. And since 2010, highly educated women have been having more children.

In other words Utah County, with its rich, expanding families, encapsulates what economists struggle to understand about American fertility. Here, it is not that the population has resisted the social forces reducing fertility elsewhere. Rather, many of the newest parents are newcomers themselves, who moved to the county to have babies. Its child-friendly infrastructure and density of young families are a potent draw. These new arrivals illustrate an underappreciated consequence of America’s changing demography. As cities across the country get greyer, would-be parents will flock to those communities that still prioritise children.

Mormons help explain Utah County’s unusual demography—but not in the way you might expect. They have long made up the majority of the county’s population. The typical temple-going adult grew up in a family with four children, two more than the average American. As birth rates fell elsewhere, Payson built more schools, adapted public spaces and provided child care. Most student housing in the neighbouring town of Provo, home to Brigham Young University, was built to include space for children. Elsewhere, women seemed to be having fewer babies in order to make time for their careers. But fewer women worked in Utah, and locally the thinking was that they would end up having similar size families to those of their mothers.

In the intervening 35 years, that is not how things have turned out. The fertility of Mormon women has dropped by more than that of the rest of the population. By 2019 more than half had fewer than three children. Birth rates are falling faster in Utah than in any other state. Yet housing, transporting and educating children is still the organising principle of these religious suburbs. That has attracted a flood of migration, mostly newlywed couples and young families from elsewhere in America. Of the 700,000 people now living in Utah County, for instance, some 100,000 have arrived since 2014. In Alpine, an affluent town nestled in the mountains on the county’s eastern border, one Mormon retiree points down his cul-de-sac. Out of 12 sprawling houses, all but his have been bought by families that arrived in Utah since 2010. A diverse set of parents now packs local museums, parks and parades.

Few demographers contemplate how new parents will behave in an ageing world. Most are still caught on the knock-on effects of fewer births. As the ranks of the elderly swell, they will soak up policymakers’ attention. A worrying consequence might be that, with little state support and few other parents, couples might have even fewer children. But many will remain determined, and seem likely to seek one another out.

Thus Utah County might provide an example for other parts of America keen to have more babies. In a study published in 2023, Matthias Doepke of Northwestern University and colleagues assessed what fertility hotspots had in common. They found that birth rates held up best in places where policymakers set up child-care schemes and introduced flexible working hours. Social norms also mattered. People living in places where adults’ social lives revolved around children tended to have more of them.

Many politicians worry about relying on migration to make up for birth shortages. Payson shows that it need not be all bad. New arrivals are rich: they have to be to afford houses in the area, the prices of which have doubled over the past decade. That provides a boost to the state’s coffers. And those moving to the area to start families also seem increasingly likely to have university degrees, which reflects a national trend. According to Mr Doepke, birth rates among the most educated women are rising.

Most big cities and populous states are not yet entirely old and grey. Still, as your columnist watches another float roll through Payson (packed with fiddlers, this time) the sheer quantity of youthful exuberance on display feels startingly unfamiliar. It is pleasant, too. How rare it is already for a town to put children at the heart of its public life. ■