Fewer Babies, Older Populations – How the U.S. and World Face a Pivotal Demographic Shift in 2025

Many researchers argue this shift is rooted in a positive development: women and young couples now have greater freedom and economic independence, leading to different choices about having children.

“It’s not that people suddenly dislike kids,” said Melissa Kearney, an economist studying fertility at the University of Notre Dame. “They simply have more options now, whether that’s investing in careers or enjoying leisure time, and it’s more socially acceptable.”

This behavior change is accelerating. Recent United Nations research shows global fertility has fallen to its lowest recorded level, with women worldwide having less than half the children they did in the 1960s.

“In higher-income countries, birth rates have dropped rapidly and consistently,” Kearney said. “We are facing real questions about declining populations.”

The Shift in American Families

In the U.S., this trend is reflected in rising numbers of women opting out of motherhood. According to Kearney, half of American women now reach age 30 without having a child, compared to one-third two decades ago. Families are also choosing to have fewer children overall.

“I remember thinking, ‘I definitely want three kids,’ just like my mom,” said Lusely Martinez, 35.

Martinez cherishes motherhood. “Watching our child grow and discover is magical,” she said. But after many conversations, she and her husband chose to have only one child.

“Raising a child is so expensive,” Martinez noted. “We had to stop and think about whether having more made sense.”

Tracking the Numbers

A straightforward way to measure this societal change is by looking at the “total fertility rate,” the number of children a woman will have in her lifetime.

A stable population requires an average of 2.1 children per woman. In the U.S., fertility dipped below this level years ago and, post-2007, dropped sharply to a record low of around 1.6.

“I don’t have a specific number that would trigger panic,” said Kearney. “But seeing so many young adults remain childless worries me that we’re missing something important as a society.”

From Population Bomb to Population Decline

The shift toward lower birth rates and aging populations is striking, especially after decades of warnings about overpopulation and its environmental consequences.

In the 1960s and 1970s, scientist Paul Ehrlich warned of a looming “population bomb” threatening the world.

“No responsible American family should have more than two children,” Ehrlich said in a 1970 interview, describing overpopulation as a fatal threat to crowded U.S. cities.

Now, many demographers say that the bomb has fizzled, and a long-term trend toward smaller populations could reduce environmental strain.

There are upsides to declining fertility: the U.N. reports a significant global drop in teenage and child pregnancies, alongside growing economic freedom for women.

“One of the major global health successes in the past 30 years has been the drop in adolescent birth rates,” said Vladimíra Kantorová, the U.N.’s chief population scientist.

Concerns About a Shrinking World

But the rapid decline in birth rates, with some countries seeing rates fall to extreme lows, worries many experts.

“In places like South Korea, the birth rate is practically nonexistent,” said economist Phillip Levine of Wellesley College. U.N. projections indicate that by mid-century, 40% of South Korea’s population will be over 65.

“No one anticipated fertility dropping this far,” Kantorová said. “We’ve never experienced such a prolonged decline before.”

While longer life spans mean the global population will continue to grow for now, these trends will lead to population declines later this century.

Countries like China, Italy, Japan, Russia, and South Korea are already seeing shrinking populations. China is projected to lose over 780 million people by 2100.

“It’s uncertain if these steep declines will happen everywhere,” Kantorová said.

The U.S. and Immigration’s Role

Despite record-low fertility, the U.S. population has remained stable thanks to immigration, but data shows a shifting demographic landscape. In 11 states, people over 65 now outnumber children, up sharply from just three states five years ago.

“Children still outnumber older adults nationwide, but the gap is closing as baby boomers age,” said Lauren Bowers of the Census Bureau.

A Brookings Institution study in 2023 found that without immigration, the U.S. population would drop by over 100 million this century.

“Without immigration, we’d lose about a third of our population by 2100,” said study author William Frey.

“What happens to our workforce? To productivity?” Frey asked. “We’ll have jobs without enough people to fill them, increasing the need for immigration.”

A Push Toward Prenatal Policies

Some politicians and activists are advocating for policies to encourage higher birth rates, known as pronatalism.

Lyman Stone of the Institute for Family Studies supports child tax credits and flexible work to make parenting more affordable, arguing many young people want kids but face barriers.

“They aren’t marrying early enough, buying homes early enough, or securing stable jobs in time,” Stone said. “So they fall short of their desired family size.”

Vice President Vance declared, “I want more babies in America,” during a March for Life speech, while Elon Musk has called declining birth rates a threat to civilization, urging people to have at least three children.

Can the U.S. Support Families for the Future?

Martinez doubts the U.S. will address underlying issues like high housing, healthcare, and childcare costs that discourage larger families.

“Why focus on increasing births if you aren’t going to support families afterward?” she said.

Experts agree that encouraging higher fertility will require significant policy changes to make parenting viable, from paid leave to affordable healthcare.

“Without a serious response, it’s not only possible but likely that fertility rates will continue falling,” Kearney said. “And I’m more worried about that than many others waiting to see if we’ll hit a point of no return.”