“Global fertility rates are grabbing the headlines. In many countries, birth rates are falling, which has prompted public policy makers to sound the alarm about the possibility of a ‘population collapse’. In an effort to blunt the demographic shifts they face, some governments are adopting draconian measures to persuade women to have more children. Nevertheless, millions of people around the world cannot have the number of children they want. In every country, regardless of its total fertility rate, the most consequential reproductive decision a person can make — when to have a child, whether to have one, and with whom — is being undermined.”
Spain is an unusual case. It is one of the countries in the world with the fewest births; a case of nearly complete population collapse. Although it has an immigrant population with many people of reproductive age, the number of births each year inside the country is very low. Why? The so-called “global fertility rate” — the number of children per woman over her lifetime — must be at least 2.1 for the country’s total population to remain stable. In Spain it is currently 1.1. There are seven births per thousand inhabitants and, at the same time, nine deaths. That translates into an annual natural increase rate of -0.2%. If this continues — and all indicators point to it continuing or perhaps falling even further — Spain could disappear in the distant future. It’s pure mathematics.
“Spain is one of the world’s countries with the fewest births; an example of near population collapse”
Of the two hundred-odd countries around the world, the ones with the lowest fertility rates — the number of children per woman — are South Korea, with 0.7 children per woman; Taiwan, with 0.9; China, with 1; Thailand, with 1; and Spain, with 1.1. I am not counting here genuinely city-states like Macao, Hong Kong, or Singapore, and to a certain extent Andorra, Malta, or San Marino. Nor the Holy See, the Vatican. Spain is therefore the European country with the lowest fertility rate. Why?
The most comprehensive birth statistics worldwide come from the Population Reference Bureau, a private entity in Washington, D.C. It computes the World Population Data Sheet, which includes more than two hundred countries dating back to 1962. The most recent statistics correspond to 2024. This kind of data collection and publication for all countries takes time, but it is a tremendously valuable resource.
There are also UNFPA statistics. It is wise to consult the report State of World Population 2025: The Fertility Crisis in Reality. Reaching Reproductive Freedom in a Changing World. The World Health Organization (WHO) also presents numerous fertility statistics.
Most sources typically handle at least two indicators. The first is the birth rate, i.e., the number of live births per 1,000 people, though it is not truly a rate in the strict sense. The second is the total fertility rate, sometimes called the “global fertility rate” — in English, total fertility rate — which estimates the number of children a woman would have over the course of her reproductive life, operationally from ages 15 to 49. The Spanish translation of fertility as fecundidad is a constant source of confusion. Fertility is the capacity to have offspring; fecundity is the actual occurrence of it. The two indicators are closely related, but they are distinct.
“The factor that best explains the decline in birth rates is the education of girls and women”
The birth rate per 1,000 inhabitants is linked to the infant mortality rate: the number of children who die before their first birthday per 1,000 live births. The decline in infant mortality is one of humanity’s greatest achievements. Its reduction helps bring down birth rates. But the factor that best explains the drop in fertility is the education of girls and women. When girls go to school, fertility tends to fall. Those women then work outside the home, delay marriage and childbearing. This is the general pattern, though it does not operate in exactly the same way in every country. Juan Díez Nicolás tackled this issue in “Birthrates in a Large Metropolis,” published in the International Review of Sociology in 1964.
Internationally, the total fertility rate correlates with the gender inequality index. Countries such as Finland, Spain, the Netherlands, Sweden, Norway, Switzerland, and Denmark have very low fertility rates and, at the same time, also show very low gender inequality. The more gender equality there is, the lower fertility tends to be. Sociologist Pau Marí-Klose suggests that, today, “women simply do not want to lead the traditional child-raising life and give up equality”.
Another factor is the rising cost of education, especially private and semi-private schooling. This leads to concentrating more family resources on offspring, particularly on a single child. Partly, this phenomenon is the cause and effect of the privatization of education. It is also linked to the model of the “nuclear family,” the most prevalent in the developed world. Television, mobile devices, media, and artificial intelligence also have a substantial — though complex to measure — impact on fertility decline.
“For years, the dangers of overpopulation and the threat that there would not be enough food to feed everyone have been emphasized”
The decline in birth rates and population decline in a country can be seen as negative features. There is something emotional about having fewer people or not having children. But for years the opposite has been stressed: the dangers of overpopulation and the threat that there would not be enough food to feed all. The Population Bomb warned of great famines that never occurred. Now, however, there are countries that wish to limit — and stabilize — their population size. Switzerland voted in 2026 on a referendum to cap its population at ten million by 2050, though the proposal was ultimately rejected. In reality, it was a right-wing populist anti-immigration initiative.
Worldwide, more than two-thirds of countries are currently below replacement level and are already losing population, especially when they do not attract enough immigrants. Nationally, many of the new problems associated with falling birth rates are solved with immigration. But on a global scale, immigration sums to zero. The surprise is that fertility rates are already low in many less developed countries. High fertility rates are concentrated in Africa.
The conservative ideology blames the drop in fertility on secularization, fewer marriages, rampant selfishness, women choosing to study and then work outside the home to become independent, the high number of abortions and divorce; in general, the postponement of marriage or non-marriage. The reality is that many people cannot find a partner to marry and take a long time to have their first child. In various cultures and countries, the general desire is to have a son. This favors higher fertility, especially in couples who have successive pregnancies because they continue to search for “a son”.
The preference for male offspring has produced in the world numerous fetal deaths of girls and infanticides of girls. But now it is different. In many developed countries, couples — when asked — acknowledge that they prefer to have a daughter rather than a son. Daughters, it is assumed, cause fewer problems, help more at home and, above all, tend to be a greater help in caring for parents in old age. The reality is that if childbearing starts later, fewer children are eventually born. Delayed marriage, as well as the high proportion of divorces, are contributing causes of the falling birth rate. Perhaps also the rise of domestic pets, dogs and cats. But they do not justify everything. No one explains why Spain’s fertility is so low.
A Diverse World
The good health of a society is not measured by the number of births each year. Quite the opposite. In the most developed countries, fewer and fewer people are being born, to the point that they must bring in more immigrants every year. In the long run, if this trend continues, the world as we know it could disappear. It starts with children not marrying, not having children, and thus no grandchildren. Some marry but divorce soon. There is no clear rationality behind these processes.
“Immigration can temporarily solve the problem for some developed countries that barely have native-born fertility”
Immigration can temporarily solve the problem for some developed countries that barely have native-born fertility. But globally, on Earth as a whole, migration solves nothing. Nor does adopting babies from China, or of other origin. China currently has a global fertility rate of 1.0, that is, less than half what would be needed to avoid disappearance. It does not attract a lot of immigration either: who would want to move to live in a totalitarian country? The so-called “Yellow Peril” was a myth spread during our childhood. What has actually happened is the proliferation of Chinese bazaars, as well as Chinese and Japanese restaurants, but in fact Chinese.
For years we were taught in school that the world would explode with so many children and that there would not be enough food for everyone in the future. Famines were foretold. Now there is concern that, if the current trend continues, several countries will disappear. In some countries, the State pays for having children or reduces taxes. But even then they do not manage to raise the low birth rates. Sociologists suspect that a rebound will not be easy. Perhaps only if the distopia of A Brave New World — actually, Brave New World by Aldous Huxley — is implemented. Gestations and births would take place in laboratories or test tubes. Perhaps that would work.
In Table 1 I present some of the birth indicators. The countries can be grouped according to their level of economic and social development. Usually, developed countries account for about 14% of the world population; developing countries make up the majority — about 73% of the population; and the least developed countries, also known as “low income,” comprise 13% of the world population. The development-based division explains the evolution of fertility and other factors. That trend is happening faster and faster. The demographic transition is taking place in less time, even before the economic development and modernization of the society itself.
Development is linked with a country’s wealth. It is a factor that fluctuates greatly. Developed countries on average have sixteen times as much wealth as less developed countries, when measuring per capita gross national income. Developed countries average around $62,000 per capita, while poorer ones have around $4,000. Birth rates depend heavily on these differences: wealthier countries have fewer births.
It is observed that births decline dramatically, down to about one-third. In developed countries there are fewer than ten births per 1,000 inhabitants; in intermediate countries around eighteen, and in the least developed countries up to 31 per 1,000 inhabitants. But much of that fertility disappears with the high infant mortality rates in the least developed countries. In those countries, four out of every hundred live births die before reaching their first birthday. In developed countries the figure is only 0.4%. The differences are thus tenfold, representing one of humanity’s greatest advances. Mortality offsets fertility, and vice versa.
“The total fertility rate is the most powerful indicator of human population growth”
The total fertility rate is the most powerful indicator of human population growth. To maintain the world’s population size, a rate of 2.1 births per woman over her lifetime is necessary. The global rate right now stands at 2.2. In other words, we are on the verge of stalling Earth’s population growth. The difference is clear depending on development level. Developed countries are losing population, with a total fertility rate of only 1.4. They compensate that decline with immigration. Developing countries have a rate of 2.3, barely above the world average. The least developed countries retain a global rate of around four children per woman on average. The global trend clearly moves toward the levels seen in the more developed countries. If that trend reaches those levels, the gradual disappearance of the human population will be a reality. But there are efforts to inhabit the Moon, and some unscrupulous minds already talk of colonizing Mars. The problem then will be how to have “Martians.”
That trend toward lower fertility is aided by the fact that the population is gradually becoming more urban and less rural. On average, more than half of the population now lives in urban areas, 58%. But the differences are evident according to development: 37% urbanized in the least developed countries, 54% in the middle, and 80% in the developed ones. Urban habitat and economic development go hand in hand and, in turn, condition fertility.
The development brings less childhood and more old age. Worldwide, a quarter of the population is still under fifteen years old. But in developed countries it is only 16%, and in the least developed 39%. The number of young people is shrinking, and there are more elderly people. Globally, only about 10% are over 65, though in developed countries it reaches 20%. In reality, those under fifteen and those over 65 form the so-called dependent population. Some compensate for others. But development slightly reduces the share of both groups, from 43% in the least developed to 36% in the developed. These data contradict the commonly held belief that dependence increases, whereas it actually decreases.
The differences are not as large in life expectancy at birth, since achieving progress in that indicator is expensive. The global average is 73 years. Depending on development, there is a gap of about 12 years. More importantly is the life expectancy of women, as they gestate and bear children. They show similar differences by development level, about 13 years. The myth is to reach one hundred years of life expectancy, but that will take a long time and effort… if it is ever achieved.
Birth rates are also closely linked to health resources and maternal–child care. Health disparities are substantial. Developed countries have about twelve times more doctors or nurses per capita. But the larger gap lies in health expenditure, which varies by nearly 128-fold depending on development level. It is almost a contradiction: the more births, the less money and personnel are available to care for them. That also helps explain differences in infant mortality rates.
Thus, crucially, development and modernization imply a sharp drop in birth rates, and even in the total fertility rate. Countries with low birth rates tend to accept immigrants, legally or illegally, into society. But on a global scale immigration sums to zero. It is surprising that fertility rates are already low in many less developed countries. High fertility rates are concentrated in Africa.
Datos cantan
The world today is not homogeneous. Diversity is the norm. Yet there is a noticeable convergence among the world’s two hundred countries toward a model of low fertility. In the long run, all countries will closely resemble each other. There is already a clear convergence in Europe. The global average is 1.6 births per 100 people, but country differences range from 0.5 to 6.4.
“The big countries —and powers— in today’s world fail to reach replacement level”
In Table 2 I present birth rates — per 1,000 people — in a selection of countries. The big countries — and powers — do not achieve replacement. Even India, a poorer country, has a fertility rate of 2.0. The United States stands at 1.6; Russia at 1.4, and China, after the “one-child policy,” is down to 1.0 child. The four countries are experiencing demographic decline. The United States attracts a lot of immigration, but China, Russia and India are not favorite destinations for migrants.
Global differences remain high. African countries in the table surpass 40 births per thousand inhabitants. By contrast, some Asian countries have very low fertility: five births per thousand in South Korea; six in China, Japan, or Taiwan. It is also very low in Italy, with six, and in Spain, with seven. Again, Spain appears as one of the world’s countries with the fewest births.
The most synthetic indicator is the total fertility rate. The global rate on the planet is 2.2, almost at the threshold of stability. But that rate ranges from 0.7 in South Korea to 6.4 in the Central African Republic. It is a rate linked to wealth/poverty. Worldwide, the youth population — especially those under 15 — still makes up about a quarter of the inhabitants. Add to this that the urban population is already more than half. We are thus looking at a world in evolution, tending toward demographic stabilization and organizing life in urban terms.
The four great powers — the United States, Russia, China and India — have low fertility rates. Yet there are opposing patterns, such as China, with a global fertility rate of 1.0, versus India, at 2.0. That is the reason India has already surpassed China in population, becoming the most populous country on Earth. They are not homogeneous countries, wealth-wise, differing by up to 8.2 times: from $10,030 per capita in India to $82,190 in the United States. Globally, they still have a substantial youth population: 17% in Russia to 25% in India. Canada, Australia and New Zealand follow a similar path, even with more urban populations. But the islands of Oceania present a different world. Samoa, which I include as a contrast, retains characteristics of low development.
“The four powers have low fertility rates. But there are opposite patterns, such as China, with a fertility rate of 1.0, versus India, at 2.0”
The most modern and demographically advanced countries are the three Asian democracies: South Korea, Japan and Taiwan. They have few young people and are highly urbanized. They represent the model of the planet’s future. But not all of Asia is like this, for Indonesia and especially Pakistan represent the less developed model. The Philippines is somewhere in between, with many young people, relatively low urbanization, and yet already reduced fertility. It is a country in transition. South Korea stands out worldwide for exceptionally low fertility and very few young people.
Central European countries fail to reach replacement level. Interestingly, Poland — traditionally a Catholic country — has one of the lowest fertility rates, 1.1. These countries fail to replace their populations, but they attract many migrants, which helps offset their declining birth rates.
The Southern European region — also largely Catholic — also fails to reach replacement. Spain has the lowest fertility rate, 1.1, together with Italy at 1.2. France manages to raise that rate to 1.6. But both Spain and France are highly urbanized: 82% of the population lives in cities.
Egypt is an example of relatively high fertility rates, with 2.6 children per woman, a large child population, 32%, and only light urbanization, at 43%. Morocco and Saudi Arabia hover around replacement. Yet other countries in the region already show modern patterns.
All Latin American countries included in the comparison are below the population replacement rate. They maintain low birth rates. Contrary to stereotype, they do not have excessive child populations. But they are very urban populations, especially Uruguay and Argentina. Cuba’s birth and fertility rates are low despite their limited development levels. Chile and Costa Rica already have very low fertility rates, of 1.2.
Africa is another world. It is the least developed region on the planet, with extraordinarily high birth and fertility rates. Many of these countries are poor, with more than 40 births per thousand inhabitants and fertility rates per woman that in several cases exceed six children on average. The proportion of children under 15 is also strikingly high, reaching almost half the population, between 46% and 49%. South Africa is an expected exception.
Worldwide, with few exceptions, the regions that currently reach replacement population levels are only Africa, the Middle East and North Africa — MENA —, and the Pacific islands. The future is clear: white and Asian populations will decline, and Black populations will increase. The world as a whole is likely to see its total population decrease.
“Spain has a very low birth rate, seven births per thousand inhabitants; a very low fertility rate per woman of 1.1”
In this global context, Spain stands out. It has a very low birth rate, seven births per thousand inhabitants; a very low fertility rate per woman of 1.1, and a small child population, 14%. Even in France this child population is higher, 17%, and in Morocco, 26%. Spain’s urban population is relatively high, 82%, similar to France, but higher than Italy and Morocco. Spain, therefore, diverges from the norm.
Preparing to lose population
The developed world is losing population. In some cases this loss is offset by immigration, precisely from developing or even less developed countries. Overall, the world still has more births — 16 per thousand inhabitants — than deaths — eight per thousand inhabitants, which translates to a positive natural increase of world population of 0.9%.
Of the four great powers, two are already losing population: Russia and China; the United States is growing by only 0.1%, while India grows naturally — births minus deaths — at 1% per year. Natural population decline concentrates in developed countries. It is Europe and the democratic Asian countries that are shrinking in population. Many attract more immigrants. Developed countries decline at -0.2%, compared with the 2.4% growth of the least developed countries.
“Of the four great world powers, two are already losing population — Russia and China; the United States grows only 0.1% and India 1%”
In Table 3 I group some of the most important countries currently losing population. They are concentrated mainly in Europe: central European countries, Southern Europe — including Spain — and, especially, Eastern Europe. In Central Europe, Germany and Finland stand out, where deaths exceed births. In Southern Europe, Greece, Italy and Portugal decline more than Spain, which falls by -0.2%. In Asia, the declines are mainly among countries that are also democracies: Japan, South Korea, and Taiwan. The region that declines most is Eastern Europe, especially Bulgaria and Belarus, but also Serbia and Croatia. Africa, the Americas, and Oceania do not yet decline in population, though they may in the future. The global pattern is a steady decline in births and an increase in mortality that hinges on advancing longevity. It is quite possible that the world population will decrease in the future.
Artificial intelligence helps little to understand Spain
Curiously, artificial intelligence lacks intelligence. It also lacks a sense of humor, irony, and sensitivity. Its explanations read like a high-school textbook. With AI we fail to ascertain the real reason Spain has one of the lowest birth rates in the world and the lowest in Europe. The reasons it offers do not explain why fertility is so low in Spain, even compared to other European countries.
“The global model is a steady decline in births and an increase in mortality that depends on rising longevity”
The AI response is the usual: high housing costs, unstable employment, later motherhood and less public support for work-family reconciliation. Add to that that many people want to have children but postpone until a safer moment, and sometimes that first child arrives too late to have more. Housing makes independent living expensive and makes it harder to start a family sooner. Precarious work and low wages cause many couples to wait for greater stability. Maternity is delayed, and that reduces the final number of children per woman. There is a lack of stable and well-funded family and child policies. The aging population and changing personal priorities also weigh, with more childless or fewer-child households.
It is not simply that people “want fewer children”; many do want them, but do not see the right moment to have them. In Spain, moreover, the generations born in the 1990s are smaller, so there are fewer women of childbearing age today than in previous decades. That worsens the decline in births, even if every woman had the same number of children. On the other hand, immigration sustains total population, but it tends to adopt, over time, the country’s reproductive patterns. Result: a population that grows little or not at all without immigration, ages rapidly, and has very few births.
Other AI queries stress the same broad factors, without explaining Spain’s peculiarity. The demographic and social reasons would be delayed motherhood, low fertility, rise of childless couples, and a shrinking pool of women in reproductive age. Among the economic and labor-related causes are precarious employment, youth unemployment, insufficient wages, and the high cost of housing. But this does not solve the question: why in Spain more?
“It’s not just that people ‘want fewer children’, but that many people want them, yet don’t see the right moment to have them”
What needs to be explained is why Spain has so few births. That, despite being a country with relatively little outright racism, attracting a great deal of immigration, especially from Latin America, and being a democratic, peaceful and religious country. Yet it is one of the countries with the fewest births in the world. In practice, artificial intelligence only offers vague, international causes: precarious employment, high housing costs, difficulties reconciling work and family, delayed motherhood, limited public support for families, cultural changes. And it concludes that Spain combines several of these factors in a particularly intense way. The peculiar thing would be the combination: people start having children late, there is a lot of economic insecurity at the age when children could be born, moving out is difficult, child-rearing support is limited, and when the first child comes along, it is often too late to have more. All of this is true, but not enough.
In Spain, fertility fell by 24% in the last decade. That has sparked a faint debate. Radio station COPE, for example, asked in December 2025 whether “Spain is running out of children.” The provisional INE data indicated 240,001 births in the first ten months of 2025, a historic low for the series. It is 24.5% lower than in the same period in 2015. The decline is partly due to a shrinking number of women of childbearing age and delayed motherhood. The public debate centers on housing, precarious work, low wages, work-family balance, the cost of raising children, and the lack of sustained government support. But that explanation remains partial. Other European countries face similar problems and do not fall to the same level.
The future is uncertain
The chances that birth rates in Spain — and in the world — will suddenly rise are small. The decline in fertility is a slow, deep, and difficult-to-reverse process. AI, for the moment, does not help to explain the Spanish case well. Everything seems complicated. It is not clear whether the answer will come from public policy, cultural change, reorganizing work life, new family forms, or simply from the acceptance of societies with fewer children and more elderly people. The future is uncertain, but the demographic trend is clear.
Over the coming decades, it may be possible to move from a world with too many births to a risk of having too few. The median age will rise and the weight of the elderly will grow. Regardless of mortality, populations will become more adult and less youthful. In some countries, schools disappear first, then the jobs tied to child-rearing. The social landscape changes. Policy also changes. Aging societies vote differently, consume differently, care differently, and fear differently. Demography is not fate, but it conditions a lot.
“The decline in fertility is a slow, deep, and hard-to-reverse process. AI, at present, does not help explain the Spanish case well”
What remains unclear is how much further fertility can fall. Today, many countries already fail to reach replacement, but they can continue to decline. No one knows where the floor lies. South Korea shows that it is possible to reach 0.7 children per woman. Spain, at 1.1, is perilously close to that group. International experience suggests that once a low fertility becomes established, economic incentives alone are not enough. It is necessary to transform the bundle of life conditions that enable childbearing. But even that may not be sufficient if desire changes, if the idea of family changes, or if people perceive child-rearing as too great a cost. The problem is material, but also cultural.
The impacts of this fertility decline are significant. It is possible that many kindergartens and then primary schools will close. There will be less demand for pediatricians, fewer children in parks, fewer teenagers, fewer university students, and fewer young workers. There will also be greater pressure on pension systems and caregiving systems. Immigration can offset this for a while, but not indefinitely. If the sending countries also reduce their fertility, that source will shrink. Moreover, immigrants tend to adopt the fertility patterns of the host country. Thus, immigration can sustain the population, but not necessarily reverse the decline in birth rates.
It is estimated that the planet’s population continues to grow, albeit at a slower pace. According to optimistic calculations, fertility could gradually rise to 1.5 by 2050 and perhaps approach 1.7 by 2070. Even then, it would still be far short of replacement. According to more realistic calculations, it could stabilize somewhere between 1.2 and 1.4. In that scenario, Spain will continue to lose native population.
“There will be less demand for pediatricians, fewer children in parks, fewer teenagers, fewer university students, and fewer young workers”
The model for developed countries — and especially democracies — is a continued decline in birth rates, with nine births per 1,000 people. Developing countries have a higher rate, around 18 per 1,000, but they are also declining. The least developed countries still register 31 births per 1,000 inhabitants, though they too will fall. The total fertility rate follows the same pattern: 1.4 in developed countries, 2.3 in the middle, and 4.0 in the least developed. Even with those analytical challenges, the global trend is clear: all countries will end up with low birth rates. Thus the question will cease to be how to curb population growth and will shift to how to organize societies that no longer grow.
In Spain, between 2015 and 2025, there has been a 24% drop in birth rates. The country now has around 49.5 million inhabitants, largely due to immigration. Over the last decade the population has grown, but not because of births. The figure is almost exactly that resident population reaches 49,442,844 people as of October 1, 2025, after growing 105,488 during the quarter. In annual terms, growth runs at about 474,000 people. All of this is due to immigration. But births continue to fall. Spain has decided to import population rather than produce it. That phrase may sound harsh, but it fairly describes the situation. Immigration sustains the economic system, the labor market, and a portion of the pension system, but it does not resolve the question of why people living in Spain have so few children. The housing crisis does not by itself explain the low fertility. Neither does the lack of nurseries. Nor employment. Nor ideology. Everything matters. Nothing suffices. Perhaps that is why, when asked of AI, it responds with a list of plausible-sounding causes that do not explain the main point. Spain is an extreme case.
There is no satisfactory explanation for why Spain has such a low fertility rate, the lowest in Europe and one of the lowest in the world. The causes are likely multiple. The consequences are easier to understand. Public policies on this matter are already debatable.
I should thank, as on other occasions, the scholar (and real academic) Juan Díez Nicolás for his excellent ideas and advice. A big thanks to Professor Pau Marí-Klose (University of Zaragoza). Also to Andrés Socias Carles (on his way to the London School of Economics). To Enrique Granda and Guzmán Carles Martí.
