Pushing the 14-day limit on human embryo research

Françoise Baylis calls for a better alignment of the science and ethics of human embryo research.

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Scientific and political elites have long known the day would come when scientists would challenge the 14-day limit on human embryo research. Indeed, Sir Robert Edwards, one of the pioneers of IVF, suggested that the limit should be 21 days. And, in Canada, as far back as 1995, the government-sponsored “Discussion Group on Embryo Research” (which endorsed the internationally accepted norm of 14 days) also noted that “this limit should be subject to modification should there be new and compelling ethical or scientific justification to do so.”

This week, two research teams – one at Rockefeller University in the United States and the other at the University of Cambridge in the United Kingdom – have reported research involving human embryos kept in vitro for 12-14 days. Prior to this there were no reports of human embryos cultured in vitro beyond nine days.  This scientific breakthrough has prompted a call to revisit the 14-day limit on human embryo research. But is this technological prowess sufficient to warrant a change in law or policy?  That is, do we have “new and compelling ethical or scientific justification” to change the 14-day rule?

The 14-day rule was initially recommended by the Ethics Advisory Board of the United States Department of Health, Education, and Welfare. Its 1979 report in Support of Research Involving Human In Vitro Fertilization and Embryo Transfer stipulated that human embryos should not “be sustained in vitro beyond the stage normally associated with the completion of implantation (14 days after fertilization).”  The proponents of this limit argued that individuality was a determinant of moral status, and that individuality could only be established once implantation was complete. Prior to the completion of implantation, two genetically identical individuals could be created by a process of twinning. As well, two different embryos could fuse together to create a single individual.

A few years later, in 1984, the Warnock Report of the Committee of Inquiry into Human Fertilisation and Embryology in the United Kingdom also recommended a 14-day limit on human embryo research. According to the Warnock Committee, the human embryo acquires moral standing sufficient to warrant its protection from invasive and destructive research with the appearance of the ‘primitive streak,’ a precursor to the brain and spinal cord (15 days after fertilization). For reasons of caution, the Warnock Committee advocated a 14-day limit on human embryo research.

From the time the 14-day rule was first proposed until quite recently, the internationally agreed-upon limit hardly mattered because scientists were unable to keep human embryos alive outside of the body for more than a few days. Ironically, now that the limit might finally be practically relevant (meaning that it could function to stop scientists from doing something they might otherwise do), the suggestion is that the limit should be revisited.

Among those who recommend a review of the current 14-day limit are some who encourage “processes aimed at consensus-building involving experts, policymakers, patients and concerned citizens.” I wholeheartedly endorse this suggestion. I worry, however, that some might be championing international consensus-building for the wrong reason. Not as a means to the end of generating appropriate legal and ethical rules and oversight, but rather as a means to the end of preventing “a public backlash and the implementation of reactive, or restrictive limits on research.” In my view, this motivation smacks of political expediency.

The aim of international consensus-building should be to better align the science and the ethics of human embryo research. One way to do this might be to critically examine a range of questions about research design and inclusion/exclusion criteria and then to carefully consider whether it might be reasonable to develop different rules for different categories of research (as defined by research objectives). Perhaps some categories of human embryo research should be limited to less than 14 days while other categories of research might be permitted beyond 14 days. Perhaps some categories of human embryo research should be limited to the use of non-viable embryos, while other categories of research might permit the research use of viable embryos. Perhaps some categories of human embryo research should prohibit embryo transfer, while other categories of research might permit such transfer. Exploring these possibilities, might help improve both the science and ethics of human embryo research.

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Françoise Baylis is a Professor and Canada Research Chair in Bioethics and Philosophy at Dalhousie University @FrancoiseBaylis