Human stem cell-based embryo models: innovation, ethics, and policy.

The aim of this White Paper is to establish a foundational framework for research, technological development, and regulation in the emerging field of stem cell-based embryo models (SCBEMs). These models, generated from Pluripotent Stem Cells, are designed to recapitulate essential events in early stages of human development. They have the potential to illuminate the early stages of embryo development and implantation and hold promise as an avenue to address global health challenges, including infertility and pregnancy loss, congenital, neonatal and adult conditions, and the need for organ transplants. While SCBEMs are not a substitute for human embryos, their tractability for large-scale analysis and their abilities to model the earliest stages of embryonic development suggest that they will have a significant impact on reproductive biology and regenerative medicine. But SCBEMs do not just raise novel scientific questions; they pose ethical and legal questions that need to be addressed. The paper stems from a meeting of a core group of researchers that met at the Institut Pasteur in Paris in November 2024 and represents the views of an extended group that has worked to elaborate the documents as a consensus for the field. Here, we provide a framework to guide research in this new field. We do this by summarizing the state of the science, assessing current SCBEM research in relation to its primary future applications and addressing the need for continued ethical and regulatory oversight associated with this new field.