From the 1980s to the early 2000s, birth rates in high and middle-income countries were stable, or at least stabilising. But over the last 10 to 15 years, across a wide range of regions, cultures, and level of economic development, they've gone into steep decline. In more than two-thirds of the world's 195 countries, the average number of children born to each woman is now below the replacement rate of 2.1. In 66 countries, the average is closer to 1 than to 2. And in some, the most common number of children born to each woman is now 0.
In 2023, Mexico's birthrate fell below that of the US for the first time, followed quickly by Brazil, Tunisia, Iran, and Sri Lanka. Lower and middle-income countries are now getting old before they get rich. The pace and breadth of decline are defying expectations. The UN projected there would be 350,000 births in South Korea in 2023. That was a 50% overestimate. The real figure was 230,000.
To be clear, falling fertility across the 19th and 20th centuries is no mystery. The consensus is that this earlier phase was driven primarily by falling infant mortality, the shift to a manufacturing and then service economy, urbanisation, and the rise of female education. What I want to focus on here is the much more recent decline, the sudden and roughly synchronised drop across very different societies after a period of relative stability.