Forget what you’ve heard about overpopulation—scientists and public figures are now warning that the real concern may be quite the opposite.
Around the world, people are having fewer children, and experts say this trend could reshape economies, societies, and even the future of civilization itself.
Elon Musk, known not just for rockets and electric cars but also for his strong views on birth rates, has long called declining fertility “the biggest risk to humanity.”
Now, a new study suggests the situation may be even more serious than previously thought.
Why 2.1 Children Per Woman Might Not Be Enough
For decades, experts believed that a fertility rate of 2.1 children per woman was the sweet spot for keeping populations stable.
But new research challenges that assumption.
According to a recent study, the number may need to be closer to 2.7 when you factor in real-life issues—like not everyone having children, gender imbalances, unpredictable health outcomes, and other variables.
One of the study’s authors, Diane Cuaresma, explained that “randomness in fertility, mortality, and gender ratios” means we need a higher birth rate to maintain population levels over time.
The Global Fertility Freefall
Worldwide, birth rates are dropping fast.
Back in the 1960s, women were having about 5.3 children on average.
By 2023, that number had dropped to 2.3. Some countries have fallen far below even that.
South Korea, for example, has a shockingly low fertility rate of 0.87—currently the lowest in the world.
Meanwhile, countries like Niger and Chad still have rates above 5, but they’re the exception.
Western nations, including the U.S., the U.K., and much of Europe, are deep in “baby bust” territory.
A Steady Decline Across the UK
In England and Wales, fertility rates have dropped dramatically in just a decade.
Some boroughs have seen a 60% decrease in births since 2013.
Today, the average woman in these areas has just 1.44 children—the lowest number since records began in the 1930s.
Nearly a third of babies born in the UK in 2023 had mothers from outside the country, raising discussions about immigration and its role in supporting the future economy.
What’s Causing People to Have Fewer Kids?
So what’s behind this global trend? Several factors are at play, starting with changing priorities.
Women around the world are choosing to have fewer children.
Education, career ambitions, financial pressure, and shifting values all influence this decision.
Increased access to contraception and reproductive health information also plays a big role.
As more women pursue higher education and careers, they often delay or opt out of parenthood altogether.
Working Women and Delayed Motherhood
More women are in the workforce than ever before—up from 52% to 72% in just a few decades.
With that shift has come a delay in starting families. In the 1940s, women typically had their first child in their early twenties.
Now, the average is well into their thirties.
While many women hope to “have it all,” the reality is that juggling work and family—especially without strong social support—often leads to fewer kids than planned.
IVF usage in the UK has skyrocketed, suggesting more people are struggling with age-related fertility issues.
Is Biology Working Against Us?
Aside from lifestyle factors, biology might also be part of the problem.
Researchers like Dr. Shanna Swan have pointed to falling sperm counts—down by more than half in 40 years—as a possible contributor.
Environmental chemicals, poor diets, smoking, and pollution are all potential culprits.
But other experts argue that the bigger issue isn’t biology—it’s simply that people are waiting too long or choosing smaller families.
Climate Anxiety and Ethical Concerns
Believe it or not, climate change is another reason some are avoiding parenthood.
A growing number of young people say they’re too worried about the planet’s future to bring children into it.
One major study showed that 40% of young adults globally are hesitant to have kids due to environmental concerns.
The logic? Reducing family size is one of the most effective ways to shrink your carbon footprint.
Are Elon Musk’s Concerns Overblown?
While Musk continues to beat the drum about population collapse—calling it the root cause of civilizational decline—not all experts agree.
Demographers argue that while some countries are shrinking, the global population will likely keep growing until the 2080s before gently tapering off.
Joseph Chamie, a former UN population expert, has even said Musk is better off sticking to cars and rockets than predicting demographic trends.
So, What Now?
Whether or not Musk’s warnings come true, one thing is clear: the world is changing.
Fewer children means fewer workers, fewer taxpayers, and more strain on systems built around the assumption of constant growth.
Countries may need to rethink how they support families, structure economies, and prepare for the future.
As Dr. Jennifer Sciubba put it: “People are choosing to have smaller families—and that change is permanent.
It’s time we plan for that reality, not fight against it.”