The Modernity Trap : Structural Constraints on Fertility in Wealthy Democracies

The "Optimistic Consensus" suggested that fertility would recover at high development levels. We test this hypothesis using panel data from 161 countries (1990–2023, N=2,989) and find no evidence of J-curve recovery. Instead, wealthy democracies converge on a synchronized fertility decline toward a total fertility rate of 1.3–1.5 as of 2023—persistently below replacement.We construct a "Modernity Index" via principal components analysis of education, gross domestic product, and urbanization, and then estimate interaction models with cluster-robust standard errors. Modernity emerges as the primary predictor of fertility decline (β=-0.68, p