Hank Greely, the director of the Center for Law and the Biosciences at Stanford University, who advised on the study, said organoid research raises a number of ethical issues. “What if the organoid has some kind of consciousness and it suffers as a result of the transplant? Or what if the transplanted animal takes on “human” characteristics?” he said. Greely does not believe these are problems today, but considers them worth discussing as the work advances. “It is not too early to think about how we could try to determine ‘society’s’ answer, if that day arrives,” he said.