Frozen potential: embryo research at the crossroads of ethics, regulation and scientific opportunity.

In an era of expanding reproductive possibilities, the human embryo has come to represent both immense potential and profound constraint. Advances in medically assisted reproduction (MAR) have led to the cryopreservation of hundreds of thousands of embryos each year, yet many remain unused and are ultimately discarded. Meanwhile, studies aimed at understanding infertility, early human development and preventing miscarriage continue to face significant barriers, with only a small fraction of embryos ever donated to research. This disconnect, shaped by regulatory ambiguity, raises a deeper question: is it more ethical to discard an embryo than to learn from it? This Perspective outlines the biological inefficiencies of human reproduction and the clinical imperative to improve MAR outcomes. We then examine the global patchwork of embryo research regulation by comparing national approaches. Drawing on examples from both clinical and research practice, we argue that permissiveness alone does not guarantee scientific progress, just as restriction does not ensure ethical integrity. A meaningful global conversation on embryo research must move beyond the binary of permissiveness versus prohibition, and toward frameworks that support responsible, transparent, and ethically grounded innovation.