The State-Assisted Reproductive Infrastructure (SARI) Model: A Conceptual Pre-Empirical Study on Institutional Design Integrating Artificial Uterus Technology, iPS-Derived Gametes, and Child Welfare — The State-Assisted Reproductive Infrastructure (SARI) Model —

This study re-examines contemporary structural problems—namely low fertility, the gendered concentration of reproductive burdens, the underdevelopment of men’s reproductive rights, and the invisibility of child abuse—under the assumption that ectogenesis (artificial uterus technology) and iPS cell–derived gamete technologies have reached practical maturity. It proposes the State-Assisted Reproductive Infrastructure (SARI) as an institutional design in which the state supplements only the shortfall in births required to maintain population stability.Declining fertility is not a matter of individual values or laziness but a rational response to the distribution of structural constraints such as bodily burdens, economic costs, and opportunity loss. As long as pregnancy and childbirth burdens remain concentrated on women, fertility behavior will tend to decline in tandem with the expansion of individual freedom, as reflected in OECD data (2023).By shifting reproduction from bodily dependence to institutional dependence, this study aims to (1) reconcile population stability with individual freedom, (2) propose the National Family Unit (NFU) as a new child welfare unit that can cover domains not fully absorbed by foster care, and show that NFUs function as a universal child welfare infrastructure open to all children, regardless of whether they were born via artificial uterus or natural birth, (3) present concrete cryptographic mechanisms to institutionally prevent eugenic selection, and (4) suggest that fertility improvement could, in the long run, mitigate stagflationary pressures in Japan. This paper is positioned as a conceptual design study prior to empirical data accumulation, and provides a theoretical foundation spanning public policy, reproductive ethics, and technology governance.