The Institute for Family Studies surveyed 1,518 US adults in 2021 and found a persistent asymmetry in how people feel about their family size decisions. The single largest group — 37% of all adults, whether currently parents or not — wish they had more children than they currently have, while 14% of parents wish they had fewer. The two figures are not symmetric instruments: the 37% is a wish-for-more aspiration that bundles parents who want another child (~24% of adults) with never-parents who still hope to start (~13%), and the 14% is cumulative family-size regret across all parities rather than regret about one specific additional child. No US survey isolates regret about a single marginal child, so the action side uses the published 14% with that broader-construct caveat made explicit. The qualitative literature on parental regret (Donath 2015, Signs) establishes the phenomenon as real and studied but supplies no prevalence rate. The desire-for-more gap reported by IFS is structural: Americans’ stated ideal family size has risen to a 50-year high while actual birth rates have fallen, meaning the aspiration-actuality divergence is widening, not narrowing.
The Gilovich and Medvec inaction-dominance model predicts that long-run regrets accumulate more on the side of things left undone than things done. The fertility evidence fits this prediction. Parents who had one more child and feel stretched rarely express the kind of persistent, escalating regret that would exceed the regret of those who stopped and later wished they had not. The IFS data show that the “wish for fewer” group among parents (14%) is well under half the size of the “wish for more” group (37% of all adults; ~24% among current parents alone), consistent with inaction-dominance. Across the population, the wish-for-more group substantially outnumbers the wish-for-fewer group, a separate signal that under-reproduction is more commonly regretted than over-reproduction.
Several limitations qualify the comparison. The action-side 14% is the published IFS figure for parents who wish they had had fewer children, but it measures cumulative family-size regret across all parities, not regret about one specific additional child — no US survey isolates the marginal-child construct, so the rate is broader than the entry’s strict “one more?” framing. The inaction-side 37% is the published wish-for-more figure, but it bundles never-parents who never made a stopping decision, so it overstates retrospective regret about voluntarily stopping. A significant share of “stopping” decisions are involuntary — fertility decline, partner disagreement, financial constraints — meaning that many people counted in the inaction side did not face a clean choice to have another child and declined; conflating structural barriers with decisional inaction can inflate the inaction-regret estimate. The IFS sources are from a think tank with a stated pro-family orientation, though the underlying survey data (US Adult Sexual Behaviors and Attitudes Study) is publicly available. Both sides of this entry measure wish-for-more or wish-for-fewer as a current preference, not a retrospective decision-regret with a validated instrument; the gap is directionally robust but should not be read as a precisely calibrated effect size.