"As of 2026, humanity is likely below replacement fertility. That has never happened
before, not in wars or pandemics. But the real surprise is that the fall has been
concentrated in low- and middle-income countries and among poorer and less educated
women. We fit a single-factor model to 236 countries since 1950: the common
component peaked in 1978, and what drives fertility down today are country-specific
trends, 219 of them negative and not one leveling off. None of the commonly cited
mechanisms can account for this pattern, so we offer a conjecture: modernity itself,
which makes a third child expensive and childlessness cheap. Children come in
integers, so it takes very little to move a cohort’s fertility rate from 1.8 to 1.3. And
nothing in an economy pushes fertility back to 2.1. We close with the main economic
consequences, in particular slow growth."
From the author of
The demographic future of humanity: facts and consequences [pdf] - https://news.ycombinator.com/item?id=44866621 - August 2025 (400 comments)
"As of 2026, humanity is likely below replacement fertility. That has never happened before, not in wars or pandemics. But the real surprise is that the fall has been concentrated in low- and middle-income countries and among poorer and less educated women. We fit a single-factor model to 236 countries since 1950: the common component peaked in 1978, and what drives fertility down today are country-specific trends, 219 of them negative and not one leveling off. None of the commonly cited mechanisms can account for this pattern, so we offer a conjecture: modernity itself, which makes a third child expensive and childlessness cheap. Children come in integers, so it takes very little to move a cohort’s fertility rate from 1.8 to 1.3. And nothing in an economy pushes fertility back to 2.1. We close with the main economic consequences, in particular slow growth."
A summary of the findings by the paper's author:
https://archive.today/F0x7C | https://xcancel.com/JesusFerna7026/status/208970285642937596...