> Demographer Ron Lee of the University of California, Berkeley, and others have shown that GDP per person, and hence living standards, are highest when fertility falls just below replacement level (around 2.1 births per woman) – to 1.6 or even less. When fertility is either much higher or much lower than that, quality of life falls off again. Lee would be worried if he was South Korea at 0.8 births per woman, or China at an estimated 1.3, he says, but England and Wales (1.6), the European Union (1.5) and the US (1.6) are all hovering around that sweet spot. [1]

[1] https://www.theguardian.com/commentisfree/2021/jul/08/why-de...