Smartphones, not economics, are driving the global fertility collapse — but the debate is contested

Smartphones, Not Economics, Are Driving the Global Fertility Collapse—But the Argument Has Gaps

More than two-thirds of the world's countries have fallen below the replacement fertility rate of 2.1 children per woman. In 66 countries, the average is closer to one than two. The pace and breadth of decline are startling: the UN estimated 350,000 births in South Korea for 2023 and was off by 50 percent, missing the actual figure of 230,000.

The Financial Times has advanced a sharp thesis to explain this phenomenon: smartphones, not economics, are the primary driver of the recent fertility collapse. The argument rests on a striking visual coincidence. When researchers adjusted fertility charts across countries to align with local smartphone adoption timelines, the fertility decline curves aligned almost perfectly. Birth rates remained stable in the US and UK until 2007 (iPhone launch), France and Poland until 2009, Mexico and Indonesia until 2011, and Ghana, Nigeria, and Senegal until 2013–2015. The effect is sharpest among younger age groups. In South Korea, in-person socializing among young adults has dropped by 50 percent over two decades. The decline holds across countries hit hard by the 2008 financial crisis and those that were not—a detail that cuts against the economic explanation.

The pattern is suggestive but not dispositive. The preponderance of evidence points to smartphones, the Financial Times argues, not economics as the culprit.

The pushback is serious.

Ross Douthhat counters that the current fertility discourse misses a deeper historical pattern. Total fertility rates have been declining since the 1800s. The real surprise was the baby boom in the 1940s–1960s, an anomaly in a century-long downward trend. If any modern population achieved that same unexpectedness, Douthhat notes, it would dominate the human future.

The economic explanation has weight. Children were once economically valuable—they worked fields, required no education investment, and raised family output. The economics flipped in the industrial and post-industrial world: children became net costs, not assets. That structural shift predates smartphones by decades.

The missing granularity.

Even if smartphones correlate with fertility decline, the mechanism remains unclear. Fertility is not uniform within populations. Some groups maintain higher-than-average birth rates while living in high-smartphone environments. The Amish, who restrict smartphone use, maintain above-replacement fertility. But the question worth pursuing is what people with higher fertility are doing differently on their phones—whether they use social media less, dating apps less, or organize in-person socializing differently—and whether that behavior is replicable at scale.

Confounding factors complicate the picture further. Millennials and Gen X spend roughly twice as much time with children as previous generations did at the same age. That time compression crowds out other activities, including serious nonfiction reading—a trend that has been misattributed to podcasts but may be more fundamental. Self-driving cars, if they arrive, could reshape attention patterns entirely, making long-form content competitive again with infinite scroll.

China presents a wrinkle. It has the world's lowest replacement fertility rate—roughly one child per family—despite sustained economic growth of 6–10 percent annually. The one-child policy certainly shaped that outcome, but the policy itself became obsolete years ago, leaving China to manage the demographic consequence without a clear policy lever.

The takeaway.

Smartphones appear correlated with fertility decline across geographies and economic conditions. But correlation is not causation, and the mechanism—whether smartphones displace time from relationship formation, alter mate selection, reduce social coordination, or simply compete for attention—remains underdetermined. Economics alone does not explain the timing or breadth of the decline, yet the deeper historical pattern of falling fertility predates digital technology by generations. The answer likely sits between the two explanations, but the granular work to isolate smartphone-specific behavioral changes within high-fertility subpopulations has not yet been done.