Falling Fertility Is Not About Opportunity Cost

Lyman Stone · 14 Oct 2025

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Something is broken in how people pair up in the West, and that shortage of couples and marriages, not money, is why there are too few children.

Their wordsThe empirical evidence strongly refutes the idea that rising opportunity costs of childbearing are driving low fertility. Declining marriage due to exogenous technology and economics shocks is tanking fertility irrespective of child direct or opportunity costs.

Also said by Alice Evans, David Heinemeier Hansson

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Every claim below was made in this piece, quoted word for word and numbered in the order the piece makes them, so you can read it there rather than take our word for it. The sentence above each quote is our reading of the claim, not their wording. Each quote was checked against a stored copy of the page at build time; where the two differ, the quote is the fact.

Our reading
Earning more does not make a woman less likely to have children, except at the very bottom of the income distribution.

Their wordsthe shift from 50th to 99th percentile earnings has no negative effect on women’s fertility, and unearned income for women has a neutral-to-positive effect
Our reading
Richer countries have fewer children than poor ones, but within a country a boom raises births and a bust lowers them.

Their wordsAlthough the cross-sectional relationship between national income and fertility is negative, the longitudinal relationship between national income and fertility is positive: economic booms create baby booms, economic busts create baby busts.
Our reading
Immigration is irrelevant to the real problem low fertility creates, because that problem is people having fewer children than they wanted.

Their wordsimmigration is mathematically irrelevant to the central policy problem of low fertility
Our reading
The harm done by low fertility is that people end up with fewer children than they wanted, not that a society runs short of workers.

Their wordsI don’t see population collapse or lack of workers as the central policy problem: the central policy problem is human happiness, human flourishing, and the freedom to live life well.
Our reading
Something is broken in how people pair up in the West, and that shortage of couples and marriages, not money, is why there are too few children.

Their wordsThe empirical evidence strongly refutes the idea that rising opportunity costs of childbearing are driving low fertility. Declining marriage due to exogenous technology and economics shocks is tanking fertility irrespective of child direct or opportunity costs.

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