The Country with the Lowest Fertility?

Most countries with low fertility rates are expected to experience population decline and demographic ageing throughout the remaining decades of the 21st century. Credit: Shutterstock

By Joseph Chamie
PORTLAND, USA, May 21 2025 – Many countries around the world have a fertility rate below the replacement level of 2.1 births per woman, but one country stands out with its exceptionally low fertility rate.

So, which country currently has the lowest fertility rate on the planet? Is that country

• Singapore
• South Korea
• Spain
• Sweden
• Switzerland?

Some additional demographic information may be helpful. This country’s fertility rate, which has been below the replacement level for forty years, declined to approximately one-third the replacement level in 2023, or 0.72 births per woman. The fertility rate in 2023 was a fraction of levels about fifty and seventy years ago, which were 3.8 and 6.2 births per woman, respectively (Figure 1).

 

 

The fertility rate of this country is expected to remain less than half the replacement level for the next thirty years and stay well below the replacement level for the rest of the 21st century.

The country has implemented various measures to address its low fertility rate, including childcare subsidies, tax reductions, childcare services, cash payments to parents, and extended maternity and paternity leave.

Fertility rates below the replacement level are becoming the global norm. In over half of all the countries in the world, representing over two-thirds of the world’s population, the fertility rate is below 2.1 births per woman

The country’s president declared population decline a national emergency and established a committee to prepare a plan to address its low fertility rate, population decline, and demographic ageing. A new Ministry of Population Strategy Planning has also been established to manage these issues.

The answer to the question of which country currently has the lowest fertility rate on the planet is the Republic of Korea, commonly referred to as South Korea.

Because of its high fertility rate in the recent past, the population of South Korea grew relatively rapidly over the past 75 years. From a population of nearly 20 million in 1950, the population of South Korea reached approximately 36 million by 1975 and about 52 million in 2025.

The past rapid growth of South Korea’s population is over and is being replaced by a rapid decline of its population.

By the end of the 21st century, the population of South Korea is expected to be approximately the same size as it was in 1950, around 22 million.

Population projections for South Korea consistently show a declining population over the coming 75 years. The various variants of United Nations population projections, for example, all show a rapidly declining population for South Korea over the coming decades.

The United Nations medium variant population projection expects South Korea’s current population of about 52 million to decline to approximately 22 million by the year 2100.

The UN’s high and low variants also project South Korea’s current population to be smaller in 2100 at approximately 32 and 14 million, respectively. The constant variant, which assumes the country’s fertility rate will remain constant at its current level, projects South Korea’s population to be 17 million by the century’s close (Figure 2).

 

 

Besides population decline, South Korea is also expected to experience rapid demographic ageing. South Korea’s young population of the recent past has been replaced by an older population that is expected to be even older in the coming years.

In 1950, the median age of South Korea’s population was about 18 years, and the proportion of the population 65 years or older was about 3%. The country’s current median age is 46 years, and about 20% of the population is 65 years and older.

South Korea’s median age is expected to continue increasing, reaching 57 years in 2050 and 60 years by the close of the century. Also, the proportion of the population aged 65 years or older is projected to reach 40 percent in 2050 and 45 percent by 2100 (Table 1).

 

Why do the population projections show a declining population for South Korea over the coming decades?

The answer to that question is relatively straightforward. South Korea is simply experiencing fewer births than deaths. In 2023, for example, the numbers of births and deaths were approximately 236 thousand and 346 thousand, respectively, yielding a natural change (births minus deaths) of -109 thousand.

The reason births outnumber deaths in South Korea is that the country’s fertility rate is well below the replacement level.

And why is South Korea’s fertility rate so far below the replacement level?

The answer to that vital question is more speculative and complex than explaining the country’s demographic trends. The answer to that question needs some context and explanation about South Korean couples having children.

It is important to recognize world demographic trends. Fertility rates below the replacement level are becoming the global norm. In over half of all the countries in the world, representing over two-thirds of the world’s population, the fertility rate is below 2.1 births per woman.

Among those many countries are some fifty populations, including South Korea, that have a fertility rate well below the replacement level. Those countries, which include China, Germany, Italy, Japan, Russia, Spain and Sweden, have a fertility rate below 1.5 births per woman (Figure 3).

 

 

Because of low fertility rates, countries are having fewer births than deaths, and that difference yields negative rates of population growth. And because of sustained levels of that negative population growth, countries are facing population decline and demographic ageing.

Various critical factors are believed to be behind the exceptionally low fertility rate in South Korea. Among those factors are higher education, a declining marriage rate, high rates of contraceptive use, lifestyle choices, difficulties finding a suitable mate, personal goals and serious concerns about the future.

Also, additional factors across South Korean society that are contributing to the country’s low fertility rate include a work culture with an exceptionally lengthy workweek, long work hours, and stiff career competition, the high costs of living, especially for housing, education, and childcare, difficulties juggling parenthood with employment, gender inequality in the workplace, particularly the gender pay gap, and the traditional gender roles and inequalities in family and household matters.

Although South Korea’s fertility rate may increase slightly in the coming decades, it is expected to remain substantially below the replacement level of 2.1 births per woman, resulting in a continuing trend of fewer births than deaths throughout the 21st century.

Many countries, including South Korea, are concerned about the decline and ageing of their respective populations. The governments of those countries are attempting to increase their low fertility rates with pro-natalist policies, incentives, and programs.

A final question concerns whether those pronatalist policies, incentives, and programs of governments will raise today’s low fertility rates back to the replacement level.

Such policies and programs may increase low fertility rates slightly. However, those increases are typically temporary and relatively small, with fertility rates remaining significantly below the replacement level.

Based on the experiences of countries over the past several decades, once a fertility rate falls below the replacement level, especially to 1.5 births per woman or less, the rate remains at low levels. Most population projections for countries with low fertility rates do not expect a return to the replacement level soon.

In conclusion, most countries with low fertility rates, including South Korea, which currently has the world’s lowest fertility rate, are expected to experience population decline and demographic ageing throughout the remaining decades of the 21st century.

Joseph Chamie is a consulting demographer, a former director of the United Nations Population Division, and author of many publications on population issues, including his recent book, “Population Levels, Trends, and Differentials”.