Mexico is in the late phase of Stage 3 of the demographic transition model and is approaching Stage 4. Its fertility rate has dropped below the replacement level of 2.1 children per woman, reaching 1.91 in 2023, while death rates remain relatively low and life expectancy sits around 70.8 years. These numbers place Mexico at the very edge of the transition from Stage 3 to Stage 4, with some demographers already considering it functionally in Stage 4 depending on the criteria used.
What Stage 3 Looks Like in Mexico
Stage 3 of the demographic transition model is defined by falling birth rates combined with already-low death rates. Population growth slows but remains positive. Mexico fits this description closely: its population is still growing, but at a pace that has decelerated sharply over the past few decades. Projections from the International Futures forecasting system put Mexico’s annual population growth rate at about 0.69% in 2026 and 0.58% by 2030, a far cry from the rapid expansion of the mid-20th century.
The reason Mexico hasn’t fully tipped into Stage 4, where population growth is near zero or slightly negative, is that its large younger generation is still moving through childbearing years. Even though individual families are having fewer children, the sheer number of people in reproductive age groups keeps total births elevated enough to sustain modest growth. By 2060, projections show Mexico’s growth rate turning negative at roughly -0.17% per year, which would firmly place it in Stage 4 or even early Stage 5.
How Mexico’s Fertility Rate Collapsed
Mexico’s fertility decline is one of the most dramatic in Latin America. In 1970, the average woman had 6.5 children. By 1979, that number had already fallen to about 5.0. The 2023 figure of 1.91 means Mexican women are now having fewer children than the 2.1 needed to maintain the population without immigration. That’s a drop of more than 70% in just over 50 years.
The turning point was 1974, when the Mexican government launched national family planning programs. Before that, government policy had actually been pro-natalist, encouraging large families. The reversal was swift and effective, particularly in urban areas where access to contraception and education expanded rapidly. Higher socioeconomic groups led the decline, but fertility eventually fell across all income levels. Research using census data from 1930 through 2015 confirms a consistent pattern: as household socioeconomic status rises, fertility drops, though the strength of that relationship has shifted over time.
The decline hasn’t been uniform across the country. Rural, Indigenous, and economically marginalized communities still have higher fertility rates than urban areas. Traditional gender roles, limited access to family planning, and gaps in education about contraception all contribute to these regional differences. This internal variation is one reason some analysts hesitate to classify Mexico fully as Stage 4: parts of the country are still experiencing Stage 3 dynamics while major cities have moved beyond them.
Mexico’s Population Pyramid Today
Mexico’s population pyramid in 2025 is classified as stationary, meaning it has a roughly columnar shape rather than the wide base typical of younger, faster-growing countries. The width of each age group is relatively uniform from the bottom up until the oldest cohorts, where it narrows. About 8.5% of the population, roughly 11.2 million people, is aged 65 or older. That share is growing and will accelerate as the large cohorts born during the high-fertility era of the 1960s and 1970s age into retirement.
This pyramid shape is characteristic of countries transitioning from Stage 3 to Stage 4. Compare it to a Stage 2 country like Nigeria, where the pyramid has a very wide base of young children, or a Stage 5 country like Japan, where the pyramid is top-heavy with elderly residents. Mexico sits squarely in between, with enough youth to keep the population growing for now but a clear trend toward an older society.
Life Expectancy and the Death Rate Side
Mexico’s life expectancy reached 74.2 years in 2000 but actually declined to 70.8 years by 2021, a drop of about 3.4 years. This is unusual for a country at this stage of development. The decline reflects the combined effects of the COVID-19 pandemic, ongoing violence, and rising rates of chronic diseases like diabetes and heart disease, which are especially prevalent in Mexico.
In the standard demographic transition model, life expectancy is expected to keep climbing or at least hold steady during Stage 3 and Stage 4. Mexico’s reversal complicates the picture. It hasn’t caused death rates to spike high enough to push Mexico backward in the model, but it does mean the country’s progression looks less smooth than textbook examples like South Korea or Brazil.
Why the Classification Is Debated
The demographic transition model is a simplified framework, and real countries don’t always fit neatly into one stage. Mexico’s below-replacement fertility rate (1.91) is a hallmark of Stage 4, yet its continued population growth and regional disparities in fertility are more consistent with late Stage 3. Different textbooks and sources will classify Mexico differently depending on which indicators they prioritize.
If you’re answering an exam question, “late Stage 3” or “transitioning from Stage 3 to Stage 4” is the safest and most defensible answer for 2025. The fertility rate has crossed the replacement threshold, the population pyramid is stationary, and growth is slowing but still positive. Within the next decade or two, as growth approaches zero, the classification will shift unambiguously to Stage 4.
Urbanization and Regional Variation
About 80% of Mexico’s population now lives in urban areas, and this concentration has been one of the strongest drivers of demographic change. Cities offer greater access to education, healthcare, and employment for women, all of which correlate with smaller family sizes. The relationship between urbanization and fertility in Mexico hasn’t always been straightforward, though. Research on Mexican census data from 1940 to 1960 found that in some cities, economic development initially coincided with rising fertility rather than falling fertility, partly because rural migrants brought higher-fertility norms into urban areas.
That pattern has long since reversed. Today, the urban-rural fertility gap persists but has narrowed considerably. The remaining pockets of higher fertility are concentrated in southern and southeastern states with large Indigenous populations and lower levels of economic development. These areas are effectively a stage or two behind Mexico’s major cities on the demographic transition timeline, which is why national-level data can obscure important local realities.