Culture and Society
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According to a new modeling study, the global average number of children a man is expected to have over the course of his life has dropped below the number expected for women for the first time in history, with the crossover happening in 2024.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.This figure – known as the total fertility rate, or TFR – is routinely tracked for women, going from about 4.9 children per woman in 1950 to around 2.3 children per woman globally in 2023.
The average number of children per man, however, is generally not measured, at least not directly. The researchers behind this study had to infer it from female fertility data and population statistics.
According to their estimates, men have until recently had a slightly higher number of children on average than women. But this gap has shrunk over time.
The reason is straightforward: as more men survive to and through reproductive age than in previous generations, the number of men grows relative to the number of women, and the average number of children per man falls.
"The key finding is that we are observing a shift from a higher total fertility rate among men to a higher total fertility rate among women, which has occurred globally in 2024," explained Henrik-Alexander Schubert, a researcher at the Max Planck Institute for Demographic Research, in a statement. "This shift is driven by an increase in the proportion of men in the population."
This imbalance stems from the fact that, naturally, around 105 boys are born for every 100 girls, a phenomenon that compensates for the fact that men and boys have historically faced higher mortality rates throughout life.
But as mortality rates have fallen globally, more boys are surviving into and through adulthood, meaning the male surplus that once faded early in life now persists well into reproductive age (though, in older age, women still outnumber men, meaning that across the entire span of the population, gender disparity is actually decreasing).
In the researchers' model, the timing of this crossover varies strongly by region. In most of Europe and North America it happened decades ago, mainly in the 1960s and 1970s. In much of Asia the transition has only occurred recently. Sub-Saharan Africa, where mortality rates remain comparatively high, is not expected to follow suit before 2100.
In some parts of Asia, the gap is widened further by sex-selective abortion. According to Our World in Data, the 2023 sex ratio at birth in China and Vietnam was 110 boys per 100 girls, for example, potentially leading to substantially more men entering reproductive age than women in the future.
"The extreme cases make up a quite substantial share of the world population," Schubert told IFLScience. "In the supplementary materials, we provide a figure that shows the world population living in countries with a difference of 5 percent or more between the [male total fertility rate and the female total fertility rate] and it shows that more than half of the world population will live in those countries [after 2030]."
"In most of the Western world the differences are very modest, and the population masculinization will have only minor implications for childlessness at the country level."
That said, the researchers do think countries projected to have the largest disparities might want to take note – particularly when it comes to strengthening the position of women in societies where son preference drives sex-selective abortion.
As the effects compound over time, another consequence is a growing cohort of childless men entering old age without family support networks. The researchers note that policymakers will need to anticipate rising demand for institutional care as a result.
The study is published in the journal PNAS.
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