Humanity’s total fertility level has dropped below the replacement rate; global population will peak around 2055 and then begin to fall, Foreign Affairs reported.
This demographic contraction challenges the foundational assumptions of modern demography. While historical population drops were driven by wars or epidemics like the Black Death, the current plunge stems entirely from human choices. As societies embrace what is often termed “modernity,” they become incapable of maintaining replacement-level fertility rates.
For decades, conventional demographic wisdom held that fertility rates invariably fell as communities grew richer and more educated. Yet that inverse relationship has completely flipped. Among members of the Organization for Economic Cooperation and Development, wealthier nations now tend to boast higher fertility rates than poorer ones.
Consider the stark disparity between Mexico and the United States. According to a 2024 survey cited by Foreign Affairs, a Mexican woman can expect to have 1.2 children over her lifetime. That sits well below the 1.57 average recorded for non-Hispanic white women in the United States, even though Mexico’s income per capita sits at roughly 28 percent of U.S. levels. Just two decades ago, those positions were reversed.
This dynamic mirrors trends within advanced economies as well. Research by demographer Martin Kolk in Sweden revealed that for all cohorts born from 1940 to 1970, males with greater lifetime earnings father more children, while the lowest birth rates among women born after the 1960s are found in the poorest group.
Regarding the United States, economists Moshe Hazan and Hosny Zoabi observed that during the first ten years of the twenty-first century, females holding graduate degrees averaged approximately 2.0 children, whereas those whose education concluded with a bachelor’s degree averaged 1.8. Wealth and education now act as buffers against the steep structural costs of modern life.
The core driver of the global baby bust is the structure of modern society itself. Modernity demands that parents equip children with formal credentials and extensive education, a multi-decade financial and logistical investment. At the same time, tight professional schedules collide directly with biological clocks, pitting career-peak years between ages 30 and 45 against the most demanding years of parenting.
When Gallup asked Americans about their ideal number of children in July 2025, the average answer landed at 2.7—a figure virtually unchanged since the 1970s. However, the financial reality of fulfilling that ideal restricts larger families to those with the capital to absorb domestic help, premium services, and advanced tuition.
Without changes to social and economic structures, economic inequality will likely intertwine with demographic inequality.
