North America once looked like an exception to the low-fertility pattern of other wealthy regions. The United States had comparatively high fertility, Canada drew strength from immigration, and Mexico remained younger. That picture has faded.
The United States has remained below replacement since 2007. Final federal data put its 2024 total fertility rate at about 1.63. The number of births rose slightly that year, but the longer movement is toward later motherhood and fewer births. Large differences by state, education, income, and ethnicity remain, yet fertility has generally converged downward across groups.
Canada reached a record-low TFR of 1.25 in 2024. Immigration has nevertheless produced periods of rapid population growth and a younger population than fertility alone would imply. Migration can offset natural decrease, though it does not erase the aging of the native-born population and it shifts growth toward particular cities. It also draws young adults away from the countries that raised them.
Mexico’s transition has been quicker than the older north-south story suggests. INEGI’s 2023 demographic survey estimated fertility at 1.6, down from 2.07 in its 2018 survey. Mexico remains younger than the United States or Canada, so momentum can sustain growth after fertility passes replacement. But the direction changes the continent’s long-run migration and age structure.
The same movement extends through much of Latin America. Countries that were associated with large young families now report fertility near or below replacement. Their institutional challenge differs from Canada’s or the United States’: aging may advance while pension coverage and formal employment remain less complete.
Three demographic balances
North American population change is the balance of births, deaths, and migration. The United States can grow slowly with below-replacement fertility because immigration and a somewhat younger age structure compensate. Canada’s recent growth has depended even more heavily on migration. Mexico may continue growing for a time because its large younger cohorts still produce many births, even at smaller family sizes.
Immigration does not repair fertility. The OECD’s review of migrant family building finds adaptation within the first generation and broad convergence toward host-country fertility across later generations, with variation by origin and age at arrival. U.S. research on Mexican migration likewise finds fertility declining within and across generations. The second generation often moves much of the way toward the native pattern. Immigration can prop up one country’s head count and labor force; at the global level, it has only shuffled people across a border.
Those differences are politically important, but they should not conceal the continental turn. All three countries now have fertility below replacement by their national measures. The remaining variation lies less in whether fertility has fallen than in how age structure and migration translate that fall into population change.
Citations
- National Center for Health Statistics, Births: Final Data for 2024.
- Statistics Canada, “Fertility and baby names, 2024”.
- Instituto Nacional de Estadística y Geografía, Encuesta Nacional de la Dinámica Demográfica 2023.
- Organisation for Economic Co-operation and Development, “Migrant family building: Recent evidence and implications”, in International Migration Outlook 2023, 2023.
- Kate H. Choi, “Fertility in the context of Mexican migration to the United States”, Demographic Research 30, 2014.