According to recent data, Nigeria records around 7.5 million live births annually, while Europe, together with Russia, see roughly 6.3 million births per year.

Nigeria’s high fertility rate, which averages around 4.6 births per woman, plays a big role in these figures. That rate is well above global averages and far higher than most of Europe, where fertility rates commonly fall below replacement level (about 1.4 to 1.6 children per woman).

By contrast, much of Europe has a deeply aged population and decades of low birth rates. Countries such as Italy, Spain and Germany have fertility well under replacement level, contributing to slower natural population growth and, in some cases, declining native population totals.

Russia in particular illustrates this trend as its fertility rate is among the lowest in the world at roughly 1.4 births per woman, and official statistics show persistent declines in the number of births as the population ages.

Low fertility rates in Europe are already prompting incentives for families, reforms in parental support, and debates about immigration policy as governments seek ways to stabilise future population size and workforce strength.

Nigeria’s youth-heavy population and higher birth rates, on the other hand, have helped it become a demographic powerhouse , even as many European countries confront ageing populations, shrinking workforces and fiscal pressures linked to elder care.

Nigeria’s demographic trends also carry implications. Rapid population growth can fuel economic expansion if accompanied by investment in education , health and employment.

The World Economic Forum suggests that "A population projected to reach 400 million by 2050 needs jobs aligned with a fast-digitising economy. But youth unemployment remains among the highest globally, with 23% of young Nigerians actively looking for work, while another 32% are out of employment altogether. Employers also report persistent shortages in technical and digital skills, underscoring the need for coordinated investment."

The data reveals some surprising global trends, with Uzbekistan leading the world at 773 ng/dl, followed closely by Croatia (752 ng/dl) and Cameroon (731 ng/dl).

Other countries in the top tier include Azerbaijan (694 ng/dl), Mongolia (693 ng/dl), and several African nations such as Ethiopia (671 ng/dl), D.R. Congo (668 ng/dl), and Nigeria (625 ng/dl).

The list also features Saudi Arabia, Sudan, and Uganda, as well as European nations like the Netherlands, Serbia, Denmark, and Croatia, indicating that high testosterone levels are not confined to one region or continent.

According to the World Population Review , testosterone levels naturally vary across populations due to a mix of genetics, lifestyle, diet, climate, and overall health. Regions with higher physical activity levels, lower obesity rates, and diets rich in proteins and healthy fats often show stronger average testosterone profiles.

However, researchers note a worrying pattern: testosterone levels are declining globally. Studies summarised by Testosterone Decline Research show that average testosterone concentrations in men have dropped significantly over the past 30 years.

Factors like environmental toxins, stress, poor sleep, sedentary lifestyles, and processed diets are contributing to this decline.

This topic arrives amid global debates about men’s health, fertility, and ageing. As societies face longer work hours, increased digital stress, and declining physical activity, hormone health has become a key public health issue.

In countries like the United States and the United Kingdom, for instance, testosterone replacement therapy (TRT) prescriptions have surged, prompting both medical interest and ethical questions around hormone optimisation.

Meanwhile, some African and Central Asian nations that top the testosterone rankings are also experiencing rapid urbanisation and dietary change, factors that may alter these rankings in the future.

In 1927, Turkey's population stood at approximately 13.6 million . Over the subsequent decades, the country witnessed significant growth, reaching 83.6 million by 2020. This expansion was particularly rapid in the post-World War II era, with annual growth rates peaking at nearly 3% in the early 1960s.

Factors contributing to this surge included high birth rates and internal migration from rural to urban areas. However, by 2020, the growth rate had decelerated to 0.6% annually, influenced by declining fertility rates and an ageing population.

Greece's population plateau and decline

Greece's demographic journey was more complex. Following the 1923 population exchange between Greece and Turkey, Greece's population in 1928 was recorded at 6.2 million. The nation experienced steady growth throughout the mid-20th century, peaking at around 11.1 million in 2010 .

However, the subsequent decade saw a decline, with the population decreasing to approximately 10.7 million by 2020. This downturn has been attributed to low birth rates, economic challenges, and emigration.

The contrasting population trends of Greece and Turkey have significant implications for their respective futures. Turkey's youthful and growing population presents opportunities for economic expansion but also poses challenges related to employment and urban infrastructure.

Greece, on the other hand, faces the challenges of an ageing population and a shrinking workforce , necessitating policy responses to address potential economic and social impacts.