Towards Clarity About the Ethics of Human-Animal Chimera Research

Ms Josephine Johnston1

1University Of Otago, Dunedin, New Zealand

So called “chimera” research is accelerating. Rapid advances in stem cell science and new gene editing techniques are enabling researchers to more extensively and precisely insert human cells—and self-organizing structures derived from human stem cells—into non-human animals at any stage of embryonic, fetal, and post-natal development. Ethics and governance questions have been raised about various kinds of chimera research, with a particular focus on studies in which human cells are mixed with those of non-human animals. Perhaps most controversially, news reports, policy changes, and journal articles over the two years have raised the possibility that scientists will mix human and non-human primate cells to create chimeric embryos and primates. Proponents of this research argue that it could advance understanding of early human development, advance understanding of neurological and psychiatric disease, and improve generation of human-compatible organs in nonhuman animals. Opponents critique the scientific justification for the research, arguing that it involves unacceptable harms to NHPs, raises unresolved ethical and oversight questions, and threatens public trust in science. This presentation identifies key conceptual and ethical challenges raised by this research and seeks clarity about what is at stake in these studies and our governance of them. From animal rights and welfare concerns, to questions about “humanization,” to weaknesses in oversight and governance mechanisms, chimera research touches on significant—and in many ways, profound—questions about our relationships with other animals, the goals of scientific research, and the basis for public trust in science. .


Josephine Johnston is a New Zealand-trained lawyer and bioethicist, who works on the ethics and law of emerging technologies, particularly as used in human reproduction, psychiatry, and genetics. She is Lecturer in the University of Otago’s Bioethics Centre and a Research Scholar at The Hastings Center in Garrison, New York.

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