What’s at stake in efforts to drop the 14 day rule for human embryo research?

Ms Josephine Johnston1

1University Of Otago, Dunedin, New Zealand

New international guidelines released in June 2021 are the first to establish ethics guidance for the study of human embryos beyond 14 days of development, marking a significant shift in the ethics of this controversial research. For over four decades, research beyond this development stage has been widely considered unethical. In at least a dozen countries it is also against the law. Now, the International Society for Stem Cell Research, a scientific society with tremendous influence over the conduct of stem cell research, has removed any time or developmental limit on laboratory cultivation of human embryos, thereby abandoning a constraint that has long assured the public that experiments such as growing human beings in a lab will forever be off limits.

In this presentation, I recount the circumstances and reasoning that led to the establishment of the 14 day rule and show that its primary purpose was not to conclusively determine the onset of moral status in the human embryo, but to enable a public policy compromise. That compromise has allowed valuable research to proceed while also signalling respect for diverse public views and offering reassurance that scientists working in this area understand the need for certain limits. I then describe the recent developments in science that promoted ISSCR to drop the 14 day rule, before identifying a range of risks associated with that decision, including for public trust in both this area of scientific research and in numerous high-stakes studies beyond this specialized field.


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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