Does the U.S. Have a Fertility Crisis?

The U.S. fertility rate—the number of children born to women of childbearing age—reached a record low in 2024. 

The average American woman between ages 15 and 44 gave birth to less than two children, raising questions about a potentially shrinking population. 

But fertility rates don’t tell the whole story of population trends. U.S. births still outpace deaths, for example, so the population is not shrinking. Fertility rates do, however, shed light on pressing issues of affordability, sustainability, and personal agency facing many would-be parents. 

How are fertility rates calculated?

There are two fertility rate calculations: 

• The period total fertility rate (TFR) is the average number of births per woman of childbearing age based on rates that occur at a specific moment in time. Each year, the CDC publishes national birth data on babies born to mothers ages 15–44 within that year and uses the average to calculate a total fertility rate. This measurement is typically displayed as the average number of children born to each woman.
• The completed cohort fertility rate groups women by age and calculates the average number of children a woman within that group has by the time she is age 44 or 49—the age at which most women are considered no longer able to have children. Cohort data cannot be accurately calculated until the youngest members of the cohort reach this age, so they don’t lend themselves to annual reports but rather to long-term studies. 

These two measurements can yield different results. For example, the U.S. had a period fertility rate of 1.64 births per woman in 2020. But when using a cohort measurement to identify average births to women born between 1959 and 1987—a cohort that was 33 or older in 2020—fertility rates ranged from 2.0 to 2.24 births per woman. 

“It may look like the total fertility rate is dropping if we look at only the period measure, but looking at the cohort fertility rate, it may remain steady,” says Linnea Zimmerman, PhD ’14, MPH, an associate professor in Population, Family and Reproductive Health. A lower period fertility rate could indicate that women are having children later, not necessarily that they are not having children at all. 

Is the U.S.’s lower fertility rate an outlier?

In 2024, the U.S. recorded its lowest ever fertility rate of 1.6 births per woman, following a downward trend in fertility rates starting in the early 2000s, and it is consistent with a global decrease in fertility rates. Data from the United Nations Population Division show that global rates were down to 2.2 births per woman in 2023, compared to 5.3 in 1963. 

“Fertility is falling across the globe, but there’s a lot of variation,” Zimmerman said in the January 5 episode of Public Health On Call. Niger, Chad, and other sub-Saharan African countries, for example, still maintain high fertility rates of over 6.0 births per woman, while South Korea’s rate is lower than 1.0. 

“There’s huge variation, but on average globally, we’re still at about 2.2 to 2.3 children being born per woman,” Zimmerman said. 

Why would a country be concerned about declining fertility rates?

Many nations strive to maintain replacement-level fertility, or to have high enough fertility to keep their population stable—neither growing nor shrinking. To achieve that, fertility rates must be at least 2.1 children for every woman. “That’s basically what a population needs to replace itself; a woman is having a child for herself and her partner,” Zimmerman explains. 

A sub-replacement level of fertility can result in economic strain. If fertility rates continue their downward trend and lead to population decline, there will be fewer workers, spenders, and savers to fuel the economy. An article from Stanford’s Institute for Economic Policy Research suggests that a smaller population could lead to fewer innovative ideas that spur economic growth. At the same time, the share of the U.S. population over 65 is growing rapidly and increasingly tapping into social services, like Social Security and Medicare, with a declining population of younger, working adults unable to shoulder the costs. This generational gap also raises questions about family caregiving for a massive aging population. 

What's behind the U.S.'s declining fertility rate?

A 2013 opinion poll found that, on average, American adults want to have between two and three children. But many feel that they can’t afford one child, let alone more. “The economy, job insecurity, housing insecurity, the cost of child care—these are all rapidly increasing, and people are feeling uncertain about their future and their ability to support a child,” Zimmerman says. 

Concerns about climate change and the environment also weigh on young people’s decisions. Even at current fertility rates, the United Nations Department of Economic and Social Affairs projects that the global population will reach 9.8 billion by 2050. Young people, Zimmerman says, worry about how many more people can fit on a planet with significant environmental challenges. 

While a declining fertility rate reflects Americans’ growing anxieties, it also demonstrates societal progress. In 2024, the largest decline in births was for teenage mothers. The fertility rate among teenagers has dropped 79% to 12.7 births for every 1,000 girls ages 15–19 from its most recent peak in 1991 of 61.8 births, proving the efficacy of interventions like comprehensive sex education and contraceptive use. “I think most of us think that’s a pretty good thing,” Zimmerman says. “But that means that the total fertility rate in the country has gone down.” 

Are there effective ways to increase fertility rates?

In the U.S., policymakers have sought to make starting a family more attainable and affordable through efforts focused on improving maternal health, lowering barriers to in vitro fertilization, and reducing the financial burden of raising children with increased tax credits and savings accounts. Other low-fertility countries in Europe and Asia have tried to increase fertility rates by offering cash allowances or one-time bonuses to parents. Yet, some have found that the impacts of these payments are muted by the cost of living—the Singaporean government has granted cash incentives of more than $8,000 to increase its fertility rate, with little success. 

A more effective approach may be policies that lower child care costs. A 2019 working paper from the UN’s Population Fund asserts that funding accessible, high-quality child care has a positive effect on fertility rates. One study of policy interventions in Western Europe found that every 10% increase in child care subsidies can increase a country’s fertility by 0.4%. Social norms can also move the needle on fertility; a 2025 paper from the National Bureau of Economic Research suggests that high-income countries where men take on more household and child care responsibilities tend to have higher fertility rates. Finally, while there is little data assessing how specific climate policies influence fertility, efforts to address environmental concerns may be necessary to assuage younger generations’ doubts about childrearing. 

The ideal scenario for fertility is one that helps people have as many or as few children as they want—“through the equitable distribution of resources, reducing the cost of living, and making sure that people have access to high quality reproductive care,” Zimmerman says. “If people are able to achieve what they want, we would probably be right around replacement level fertility.”