The rapid rise of stem-cell-based embryo models comes with new ethical, technical, legal, and even conceptual challenges. With biologists, ethicists, philosophers, and lawyers both within and outside of the SUMO consortium, we are actively involved in the establishment of criteria for standardization, lay-out frameworks for ethical evaluation, and further conceptualize embryo models as a tool of scientific discovery. We combine these scientific endeavours with an active role in the public debate and ample outreach, to ensure the field can progress with both public and scientific trust.