“No existe el derecho a ser abuela,” Marina tells her mother, Abigail. The 38-year-old lawyer in Buenos Aires is not being cruel; she is stating a generational fact. Abigail, now 75, had imagined a retirement ringed with grandchildren, just as she had once seen motherhood as the natural completion of a woman’s life. Marina sees it differently: her career, her travels, her cats. The exchange, captured in a recent study by the Universidad Austral, is not a private quarrel but a live nerve in a global conversation about why people are having fewer children—or none at all.

A sweeping new survey from the UN Population Fund (UNFPA), released this week, challenges the notion that young adults are rejecting family life out of selfishness or ideological shift. Drawing on responses from 108,000 internet-connected adults aged 18 to 39 across 73 countries, the Demographic Futures Survey finds that the desire for parenthood remains stubbornly high: among childless 35-to-39-year-olds, 79 per cent of men and 72 per cent of women still want to become parents. What has changed, the report argues, is the economic ground beneath their feet. Financial constraints, not feminism, are the primary brake on fertility. The UNFPA notes that public debate has long asked the wrong question—whether young people still value family—rather than examining what conditions they need to form relationships and raise children.

Viewed from Jakarta, that diagnosis resonates. Indonesia’s deputy minister for population and family development, Isyana Bagoes Oka, observed this week that for many young Indonesians, building a family remains a life aspiration, but one colliding with “economic uncertainty, access to decent work, the high cost of education and housing, and the challenge of balancing family and career.” The phrase that has become a generational shorthand—“in this economy”—is, she suggested, not a joke but a structural barrier. The numbers bear this out. The UN reports that the global average number of births per woman has fallen from around five in the 1960s to just above two today, with more than half of all countries now below the replacement rate of 2.1. In Argentina, births have nearly halved in a decade, from 777,012 in 2014 to 413,135 in 2024, a decline so steep that the country now sits alongside Chile, Uruguay and Costa Rica in Latin America’s ultra-low-fertility club.

This demographic drift is already rewriting women’s health risks in ways that researchers are only beginning to map. A study published in The Lancet Regional Health–Americas found that while breast cancer mortality has fallen among Argentine women over 45, it has been rising among younger women since 2010, with the sharpest increases in the country’s northwest. The authors point to changing reproductive patterns—fewer pregnancies, shorter breastfeeding periods—as a likely contributor. Meanwhile, an analysis of Global Burden of Disease data forecasts that the number of women experiencing infertility worldwide will reach 80 million by 2036, a 1.5-fold increase from 2023, driven largely by delayed childbearing. In Italy, the Ibdo Foundation’s obesity barometer flagged a doubling of obesity prevalence among women aged 18 to 34, a trend its president, Paolo Sbraccia, called “a progressive slippage” with implications for maternal and infant health.

What emerges from these disparate data points is not a simple story of rejection. The Universidad Austral survey found that among Argentines who do not want children, 57.3 per cent say parenthood simply does not form part of their life project—a figure that for the first time outstrips economic or professional reasons. Yet the UNFPA survey complicates that picture: most respondents cited the joy and happiness children bring as their reason for wanting to become parents. The tension is not between wanting and not wanting, but between longing and the conditions that make longing actionable. In a clinic in Rome, a young woman hears that her weight may affect her future fertility; in a flat in Buenos Aires, Marina’s mother slowly absorbs a sentence that rewrites her own past. The arithmetic of family is being recalculated, not in the abstract, but in millions of private conversations that begin with a daughter’s quiet refusal of a future her mother assumed was inevitable.