ABSTRACT
Despite expanded family policy spending across high-income countries, fertility remains low. Quasi-experimental evidence shows that cash and tax transfers tend to shift fertility mainly among lower socioeconomic status (SES) groups, with smaller or null effects among socioeconomically advantaged groups. We propose a two-constraint framework that distinguishes financial constraints (children are unaffordable) from organizational constraints (care is difficult to coordinate with work, mobility, and daily life). Using the evolutionary anthropological lens of cooperative rearing, we specify four organizational functions needed to translate fertility intentions into births: proximity to trusted helpers, schedule-compatible temporal coverage, relational durability, and insurance against disruptions. A theory-based integrative review suggests that policies that expand cooperative capacity—through childcare hours and continuity, schedule predictability, and proximity-supporting infrastructure—are more likely than cash alone to affect parity progression when affordability is not the primary constraint. We interpret fertility-related policy as autonomy-enhancing and well-being-enhancing family infrastructure rather than demographic engineering and derive falsifiable propositions for future research.