Tech billionaire Elon Musk has once again voiced his growing concern over what he believes is humanity’s most significant existential threat: declining birth rates. Reacting to a recent social media post that cited a Fortune report on demographic trends, the Tesla and SpaceX founder stressed the alarming consequences of modern fertility patterns and emphasized the need for higher birth rates to avoid long-term societal collapse.
The discussion was triggered by a post shared on X (formerly Twitter) by user Mario Nawfal, who drew attention to findings suggesting that the often-cited replacement rate of 2.1 children per woman is no longer sufficient to maintain stable population levels. Nawfal wrote, “Scientists now say 2.1 kids per woman won’t cut it — 2.7 is the real number needed to avoid long-term extinction. Right now, the U.S. is at 1.66, and most rich countries are even lower, including Italy at 1.29 and Japan at 1.30.”
Nawfal explained that the revised figure of 2.7 children per woman takes into account various social and biological factors such as the growing number of people who remain childless and gender disparities at birth. In support of the post, Elon Musk reiterated the significance of addressing the trend by reposting Nawfal’s data and adding his own comment: “People who have kids do need to have 3 kids to make up for those who have 0 or 1 kid or population will collapse.”
Musk has long linked demographic decline to the downfall of great civilizations, most notably the Roman Empire. “Low birth rates were the primary factor in their downfall — shockingly overlooked by most historians,” Musk previously said, pointing out how historical societies failed to recognize the risks of unsustainable fertility levels. He considers the matter not just a demographic or statistical challenge, but a civilizational one, warning of long-term ramifications. As he put it, “If you don’t believe me now, just wait 20 years.”
His advocacy is not without personal commitment. Over the last 20 years, Musk has become a father to 14 children. His journey into parenthood began in 2002 with the birth of Nevada Alexander, his first child with then-wife Justine Wilson, a Canadian author. Tragically, Nevada died of sudden infant death syndrome at only ten weeks old. Musk and Wilson went on to have five more children: twins Vivian and Griffin, followed by triplets Kai, Saxon, and Damian. Since then, Musk has had additional children, making him one of the most high-profile figures to practice what he preaches in terms of contributing to population growth.
Concerns about declining fertility rates are not limited to Musk and independent commentators. International agencies are now addressing the issue with growing urgency. A new report from the United Nations Population Fund (UNFPA), titled “The Real Fertility Crisis,” highlights the widespread nature of low fertility levels and the growing number of people unable to meet their desired family size.
“If you don’t believe me now, just wait 20 years,” Musk emphasized again in light of the UN’s findings.
The 2025 State of World Population (SOWP) Report by the UNFPA is particularly significant because it marks one of the agency’s most explicit acknowledgments to date of the challenges associated with global fertility decline. The report found that hundreds of millions of people globally are not having as many children as they would prefer. Two of the most commonly cited reasons are the escalating financial burden of childrearing and increasing difficulty in finding compatible partners.
India, the world’s most populous country, is also seeing fertility rates dip below the replacement threshold. According to the report, India’s total fertility rate has now decreased to 1.9 births per woman. This is a major shift from earlier decades when families in India were much larger. Andrea M Wojnar, UNFPA’s India Representative, credited the decline to improvements in education and better access to reproductive health services. “India has made significant progress in lowering fertility rates – from nearly five children per woman in 1970 to about two today, thanks to improved education and access to reproductive healthcare,” Wojnar said.
Musk’s alarmism may strike some as exaggerated, but his consistent messaging is gaining traction as more global data points to a steady decline in birth rates, particularly in developed and rapidly developing countries. He sees the risk as both mathematical and civilizational — a slow but potentially irreversible shift in the structure of human society. While some experts caution against overreaction, others acknowledge that fertility decline could lead to a host of economic and societal issues, such as aging populations, labor shortages, and reduced economic growth.
The UNFPA report seeks to clarify that the problem is not necessarily overpopulation, as previously believed, but rather the growing mismatch between fertility aspirations and reality. Economic pressures, career priorities, social isolation, and changing gender roles are all contributing to people choosing to have fewer or no children.
Elon Musk’s views place him among a small but vocal group of public figures calling for a reevaluation of societal attitudes toward parenthood and family size. His insistence that “people who have kids do need to have 3 kids” stems from the idea that demographic stability cannot be achieved if most people have only one or two children, especially when others have none. It’s a simple numbers game, he argues — one that humanity is currently losing.
By referencing ancient Rome and other past civilizations, Musk is also making a cultural and historical argument. He believes that like Rome, modern societies risk falling into decline if they fail to maintain robust population growth. His call to action isn’t just aimed at policymakers or economists but at everyday citizens who can help reverse the trend through family-building.
While some critics question whether increasing birth rates is the correct or most ethical solution — especially considering environmental concerns and resource distribution — the concern about aging populations and shrinking workforces is already playing out in countries like Japan, South Korea, and Italy. These nations are grappling with pension crises, labor gaps, and diminished innovation capacity due to shrinking youth populations.
Musk’s message, therefore, is as much a warning as it is a challenge. With his blend of data, historical context, and personal commitment, he continues to advocate for a fundamental rethink of modern reproductive priorities. As he warned once again, “If you don’t believe me now, just wait 20 years.”
