Parents explain 62% of missing babies in rich nations — childlessness just 38%
Parents — not childless adults — account for nearly two-thirds of plummeting birth rates worldwide, with mothers in countries like Spain and Russia now averaging just 1.7-1.8 children each
A new NBER working paper "Childless or Child-fewer?" by economists Michael Geruso and Dean Spears (University of Texas) give us a bit more nuance on falling birthrates. Their analysis shows birth rates would trigger depopulation even if everyone had children, because parents themselves are averaging fewer than two kids.
By the numbers: New research from economists Michael Geruso and Dean Spears reveals:
62% of fertility decline in advanced economies stems from parents having fewer children
Only 38% comes from increased childlessness
0.25 births — the average fertility drop per woman over 20 years across studied countries
17 of 19 countries saw fertility decline (only U.S. and Denmark bucked the trend)
272 of 683 country-cohorts show mothers averaging below 2.1 children
120 million Indians live in districts where even mothers average below replacement
In India, childlessness accounts for just 6% of the massive 2.17-child gap between high and low-fertility districts
The big picture: Even excluding childless adults entirely from calculations, average births among parents have fallen below the 2.1 replacement threshold in:
12 of 31 countries studied (including Spain, Russia, and parts of Japan)
41 Indian districts covering a population the size of Japan
Reality check: In Russia, mothers averaged 2.4 children in the 1940s birth cohort — today it's 1.8. Spain and Taiwan show similar collapses, with parents now averaging fewer than 2 kids.
Zoom out: This isn't new. The Human Fertility Database shows mothers have been averaging below-replacement fertility since cohorts born in the 1960s in several countries — meaning this trend predates today's childlessness debates by decades.
More details:
Japan's dual crisis: Childlessness surged from 15% to 27% between 1959-1979 cohorts, but even Japanese mothers now average just 2.03 children — below replacement
Data Source: Analysis uses the Human Fertility Database (high-quality vital records from 34 countries spanning 1935-1979 births) plus India's nationally representative 2019-2021 survey of 1.4 billion people
India’s rapid fall: At similar fertility levels, Indian districts show 7 percentage points lower childlessness than wealthier nations — yet states like Goa and Sikkim already see mothers averaging below 2.0 children
The U.S. paradox: While global fertility crashed, American births actually rose from 1.99 to 2.20 between 1958-1978 cohorts — the only country showing meaningful increase. America's recent decline differs too, with childlessness playing a bigger role than elsewhere
Poland's plunge: Shows the most dramatic shift — childlessness more than doubled (9.6% to 22.5%) while mothers' average births dropped from 2.44 to 1.95
What they're saying: "In many populations, average birth rates even among parents would be low enough eventually to cause depopulation," the authors write, directly challenging what they call "widespread recent narratives."
Yes, but: Lyman Stone's 2020 claim that 'the main cause of declining fertility in America is increasing childlessness' turns out to be right — but only for America. Wall Street Journal analysis confirms the U.S. is the outlier, while this paper argues on a global level, it's parents having fewer kids (62%) not more people going childless (38%) that drives the baby bust.
Between the lines: The magic number isn't always 2.1 — replacement rates vary by mortality (2.39 in India's Uttar Pradesh vs 2.09 in wealthier Kerala). But parents everywhere are falling short of their local thresholds.
Bottomline: Japan's dual collapse proves both problems demand action: childlessness doubled to 27% while mothers' average crashed to 2.03 children. Yes, parents having fewer kids drives 62% of fertility decline globally, but 38% from childlessness is massive. Countries must expand who becomes parents AND help those parents have more children. Single-lever policies will fail. When mothers in Taiwan average 1.8 kids, every birth matters, whether it's someone's first or third.
This goes to support the idea, once again, that economic factors affect family formation for those that do want to have children just as much as anything else.
As we know, both the two-income households and the general increase in costs of living mean that having more than one child is becoming a challenge, while the culture provides a perverse feedback loop to the process, where more of the life is centred on childless adults and children are becoming and afterthought in public spaces.
Interesting discussion.
It would not be surprising to me that childlessness is not the only cause of fertility decline. It’s also a matter of people who want children preferring to have fewer of them.
This also signals, as Dave points out, that reversing this trend, should that be the goal, will require multiple policy levers to be pulled. I have evaluated a few of those policy measures, and none of them appear to work particularly well.