From naïve pluripotency to chimeras: a new ethical challenge?

In recent years, there has been much interest in the prospect of generating and using human stem cells that exhibit a state of naïve pluripotency. Such a pluripotent state might be functionally confirmed by assessing the chimeric contribution of these cells to non-human blastocysts. Furthermore, the generation of naïve human pluripotent stem cells in vitro could lead to the creation of chimeric animal models that can facilitate the study of human development and disease. However, these lines of research raise thorny ethical concerns about the moral status of such chimeric animals. Here, I call attention to these ethical barbs and suggest a way in which to proceed cautiously.