Why Low Fertility Persists: Functional Differentiation, Temporal Desynchronization, and the Limits of Steering

Objective: This article explains why fertility has remained persistently low across heterogeneoussocieties despite policy interventions.Background: Across heterogeneous late-modern societies, fertility has converged to subreplacement levels. Existing explanations emphasize shifting values, gender norms, social policy,or diffusion mechanisms, but they pay less attention to how non-parenthood becomes bothcommunicatively legitimate and structurally probable. Luhmannian systems theory offers toolsto analyze how increasing functional differentiation reshapes the conditions under whichreproduction is decided and coordinated.Method: The article develops a conceptual model informed by Luhmannian systems theory. Itexamines how intimate interaction systems are structurally coupled with economic, educational,legal, political, and medical systems, and how these couplings generate temporaldesynchronization between individual reproductive windows and institutional time. The analysissynthesizes demographic trends and policy debates to illustrate the argument.Results: Functional differentiation decouples intimacy from multifunctional family roles andmakes reproduction structurally optional. As temporal misalignments deepen, the probability ofsuccessful coordination for childbearing decreases, especially under high educational and careerdemands. Because family policies operate as programs within other systems’ binary codes, theirimpact remains modest and context-dependent and cannot fully re-synchronize divergent timestructures.Conclusion: Persistently low fertility emerges from system autonomy and temporalmisalignment across function systems, which helps explain why durable fertility rebounds areunlikely under current structural conditions.