In 1963, the average woman worldwide had 5.3 children over her lifetime. By 2023, that figure had more than halved to 2.2, a decline that occurred while the global population nearly tripled, from about 3.2 billion to 8.1 billion people. This is the central paradox of the modern demographic era: fertility fell faster and further within six decades than at any comparable point in recorded history, even as the number of people on Earth kept climbing, propped up by lower child mortality and longer lifespans working in the opposite direction of falling births.
The Global Fertility Story in One View
The scale of this decline is best understood against the population growth that accompanied it. Global fertility fell from 5.3 births per woman in 1963 to 2.2 in 2023, while the world’s population rose roughly 150 percent over the same period, from 3.2 billion to 8.1 billion.
That combination, fertility falling by more than half while population grew two and a half times over, is only possible because the number of women of reproductive age was itself rising throughout most of this window, and because falling child mortality meant far more of each generation’s births survived into adulthood than in earlier eras.
Global Fertility Rate and Population, Selected Years
| Year | Global Fertility Rate (Births per Woman) | Global Population |
|---|---|---|
| 1963 | 5.3 | approximately 3.2 billion |
| 1990 | 3.3 | approximately 5.3 billion |
| 2023-2024 | 2.2 to 2.25 | approximately 8.1 to 8.2 billion |
Source: Statista, “Total Fertility Rate,” compiled from UN DESA World Population Prospects; United Nations World Population Prospects 2024: Summary of Results.
When Fertility Began Falling
Fertility decline did not begin simultaneously everywhere; it followed the broader demographic transition already established in Europe and North America well before the mid-20th-century starting point most global statistics use. What changed after the 1960s was the speed and geographic breadth of decline: fertility began falling in large parts of Asia and Latin America within just a few decades, compressing a transition that had unfolded over a century and a half in Europe into a fraction of that time.
Why Families Began Having Fewer Children
The forces driving fertility decline across different regions and eras overlap substantially, even though no single cause fully explains every case.
Declining child mortality reduced the practical need for high fertility as a hedge against child death, a dynamic especially visible in the sequencing of transitions worldwide, where mortality decline has almost always preceded fertility decline by a meaningful lag.
Rising female education consistently correlates with lower fertility across virtually every region studied, both by delaying the age of marriage and childbearing and by raising the economic opportunity cost of additional children.
Urbanization converts children from net economic assets in agricultural households into net economic costs in urban settings, where children require years of costly education rather than contributing early farm labor.
Expanding access to contraception has allowed couples in an increasing number of countries to align actual family size more closely with their stated preferences, which in most surveyed populations has trended smaller over time.
Different Countries, Different Fertility Paths
The pace of fertility transition has varied enormously by region, and comparing that pace illustrates how compressed the more recent transitions have become relative to history’s first cases. Europe’s fertility decline unfolded gradually across roughly a century and a half beginning in the late 1700s.
East Asian economies, by contrast, saw fertility fall from levels comparable to today’s highest-fertility countries to well below replacement within just a few decades in the latter half of the 20th century. Latin America followed a broadly similar accelerated pattern from the 1960s onward.
South Asia’s transition has been more gradual and internally uneven, and Sub-Saharan Africa remains earliest in this global sequence, still recording the highest regional fertility rate in the world even as its own decline continues.
The Rapid Fertility Declines in Asia and Latin America
East Asia’s fertility collapse stands out even among rapid transitions for its speed and its current extremes. South Korea’s fertility rate has fallen to among the very lowest ever recorded for any country, part of a broader East Asian pattern that also includes Japan, Taiwan, and Hong Kong, all of which transitioned from high fertility to sub-replacement levels within a single generation, driven by rapid industrialization, urbanization, and, in China’s case, decades of direct state family planning policy.
Latin America’s transition, while somewhat less compressed than East Asia’s, similarly moved many countries in the region from fertility rates well above replacement in the 1960s to at or below replacement by the early 21st century.
Fertility Transition in Sub-Saharan Africa
Sub-Saharan Africa’s fertility transition remains the least complete among major world regions, though genuine progress is underway rather than absent. The region’s overall fertility rate has been declining gradually from the levels recorded around 2000, even as it remains, at well above 4.0 children per woman, the highest of any region in the world.
This regional average, however, obscures substantial internal variation: fertility in parts of Southern Africa has fallen much closer to global averages, while countries such as Niger, Chad, Somalia, and the Democratic Republic of the Congo, covered in more detail in analyses of the world’s highest-fertility countries, remain well above 6.0 children per woman, illustrating that “Sub-Saharan Africa” describes a wide range of fertility experiences rather than a single uniform pattern.
The Rise of Ultra-Low Fertility
At the opposite extreme from Niger’s fertility rate of over 6, a growing number of countries have fallen into what demographers describe as ultra-low fertility, generally defined as below 1.4 children per woman.
Within Europe specifically, fertility levels vary widely even among developed economies: Monaco recorded the highest fertility rate in Europe in 2024 at 2.1 children per woman, essentially at replacement level, while large countries fared far worse, France led among large European countries at just 1.64, and Ukraine recorded the lowest rate on the continent, at approximately 1 child per woman.
Selected European Fertility Rates, 2024
| Country | Total Fertility Rate |
|---|---|
| Monaco | 2.1 (highest in Europe, small population) |
| France | 1.64 (highest among large European countries) |
| Ukraine | approximately 1.0 (lowest in Europe) |
Source: Statista, “Total Fertility Rate in Europe in 2024, by Country,” compiled from UN DESA data.
East Asia has produced some of the most extreme examples of ultra-low fertility recorded anywhere, with South Korea’s rate falling into territory well below even the 1.4 threshold in recent years, a level low enough to imply, absent any change, a population roughly halving with each successive generation if sustained indefinitely.
Why Fertility Can Fall Below Replacement
Ultra-low fertility reflects a distinct and partially separate set of pressures from the mortality-and-education-driven decline that characterizes the earlier stages of fertility transition covered above. Delayed childbearing, often driven by extended education and career establishment, compresses the biological window available for having children, particularly when combined with housing costs and labor market pressures that make starting a family later in life more financially feasible than starting earlier.
Persistent gender role imbalances in many countries, where women continue to bear a disproportionate share of domestic and childcare responsibilities even after entering the paid workforce in large numbers, have been linked in multiple national contexts to fertility settling below what women in surveys often report as their desired number of children, an important distinction between period fertility rates and the family size people say they actually want.
What Low Fertility Means for Population Size
The connection between falling fertility and eventual population decline is neither immediate nor automatic, a distinction covered in depth in analyses of population momentum. A country’s fertility rate can fall below replacement for one, two, or even three decades before its total population begins actually shrinking, because a still-large cohort of people in their reproductive years, a legacy of earlier higher fertility, continues producing births even as each woman has fewer children on average. This lag explains why countries like China saw fertility fall below replacement in the early 1990s yet did not see their total population begin declining until roughly three decades later.
The Future of Global Fertility
UN DESA’s own World Population Prospects 2024 projects that global fertility will continue its multi-decade decline, though the pace and ultimate trajectory carry meaningful uncertainty, as reflected in the UN’s own downward revision of its long-run population projections between its 2013 and 2024 editions, driven substantially by fertility falling faster than previously modeled in several major countries. The broad direction, however, is not in serious dispute among demographers: more countries are expected to cross below replacement fertility in the coming decades, even as a smaller number of high-fertility countries, concentrated overwhelmingly in Sub-Saharan Africa, continue the same gradual decline from a much higher starting base.
Conclusion
The fertility transition captured in the fall from 5.3 to 2.2 children per woman between 1963 and 2023 is arguably the single most consequential demographic shift of the modern era, reshaping everything from workforce size to pension systems to the population pyramids examined throughout global demographic research.
What makes the current period distinct is not the direction of change, fertility decline has been the dominant global pattern for over a century, but its geographic breadth and, in an increasing number of countries, its overshoot well below replacement level into ultra-low fertility territory that has no clear historical precedent for how, or whether, it eventually stabilizes.
Frequently Asked Questions
1. How much has global fertility declined since the 1960s?
Global fertility fell from 5.3 children per woman in 1963 to 2.2 in 2023, a decline of more than half within roughly six decades, even as world population rose from 3.2 billion to 8.1 billion over the same period.
2. Why did fertility rates fall as countries developed?
The most commonly cited factors include declining child mortality, which reduces the need for high fertility as insurance, rising female education, which delays childbearing and raises its opportunity cost, urbanization, which turns children into economic costs rather than assets, and expanding contraceptive access.
3. Which regions have seen the fastest fertility declines?
East Asian economies, including South Korea, Japan, Taiwan, and China, experienced some of history’s fastest fertility transitions, moving from high fertility to well below replacement within a single generation in the latter half of the 20th century.
4. What is ultra-low fertility?
It generally refers to a total fertility rate below approximately 1.4 children per woman, a level now recorded in numerous countries, especially in East Asia and parts of Southern and Eastern Europe.
5. Which country has the lowest fertility rate in Europe?
Ukraine recorded the lowest fertility rate in Europe in 2024, at approximately 1 child per woman, while France led among large European countries at 1.64.
6. Why is Sub-Saharan Africa’s fertility transition happening more slowly?
The region’s transition remains earlier-stage than other parts of the world due to a combination of continued relatively high infant and child mortality, agricultural economic structures, more limited contraceptive access, and social factors, though fertility is declining gradually across most of the region.
7. How is falling fertility linked to population decline?
Falling fertility does not cause immediate population decline due to population momentum; a country can spend one to three decades below replacement fertility before its total population actually starts shrinking, since a large existing cohort of reproductive-age people continues producing births in the meantime.
8. What is the difference between period fertility and completed fertility?
Period fertility measures the fertility rate observed in a single calendar year, while completed fertility measures the actual final number of children a specific cohort of women has over their full reproductive lifetime; the two can diverge, particularly when childbearing is being delayed rather than permanently foregone.
9. Will global fertility keep falling?
Most demographic projections, including the UN’s World Population Prospects 2024, anticipate continued fertility decline globally, though the UN has itself revised its projections meaningfully between editions as fertility fell faster than expected in several major countries, indicating real uncertainty in long-range forecasts.
10. Are any high-fertility countries seeing their rates rise rather than fall?
No major country has demonstrated a sustained fertility increase after entering decline; even the world’s highest-fertility countries, such as Niger, have shown gradual downward trends in recent years, consistent with the broader global transition rather than a reversal of it.
Sources
- Statista, “Total Fertility Rate” chart, compiled from UN DESA World Population Prospects data, 2023
- United Nations Department of Economic and Social Affairs, World Population Prospects 2024: Summary of Results
- Statista, “Total Fertility Rate in Europe in 2024, by Country”
- Statista, “Countries With the Highest Fertility Rate in 2024” and “Fertility Rates in 2023”
- Macrotrends, Niger Fertility Rate 1950-2025
