The Power of Flexibility: How Synergistic Labor and Generous Leave Policies Drive Fertility Across Households

Matthew Parbst , Bocconi University
Letizia Mencarini, Bocconi University
Arnstein Aassve, Bocconi University
Hande Tugrul, Bocconi University

Why do similar family policies yield different fertility outcomes across contexts? This study develops and tests the Life Course Synergy Framework (LCSF), which argues that fertility responds not to individual policies but to their synergistic interaction. Using fixed-effects Poisson models with European Social Survey data from 15 countries (N = 8,182 mothers aged 18–45), we examine how combinations of paid leave, early childhood education and care (ECEC), and workplace flexibility (flextime) shape fertility across the household income distribution. Our key finding challenges demographic theory: under conditions of high leave spending and high flextime availability, the traditionally negative relationship between income and fertility reverses—higher-income mothers have more children than lower-income counterparts. Neither policy alone produces this effect; only their synergistic combination allows higher-income women to reconcile career and family roles. This reversal suggests that “lowest-low” fertility among educated women reflects institutional failure, not immutable preferences. The findings reconcile conflicting evidence from single-policy studies and demonstrate that comprehensive, coordinated policy packages can reshape even entrenched demographic patterns. For policymakers confronting population aging, the implication is clear: piecemeal reforms will fail. Only integrated strategies that recognize policy complementarities can advance both gender equality and sustainable fertility.

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 Presented in Session 41. Fertility, Family Policies and Labour Markets