Rethinking Human Embryo Research Policies

Abstract

It now seems technically feasible to culture human embryos beyond the “fourteen‐day limit,” which has the potential to increase scientific understanding of human development and perhaps improve infertility treatments. The fourteen‐day limit was adopted as a compromise but subsequently has been considered an ethical line. Does it remain relevant in light of technological advances permitting embryo maturation beyond it? Should it be changed and, if so, how and why? What justifications would be necessary to expand the limit, particularly given that doing so would violate some people's moral commitments regarding human embryos? Robust stakeholder engagement preceded adoption of the fourteen‐day limit and should arguably be part of efforts to reassess it. Such engagement could also consider the need for enhanced oversight of human embryo research. In the meantime, developing and implementing reliable oversight systems should help foster high‐quality research and public confidence in it .

ISSCR Guidelines for Stem Cell Research and Clinical Translation: The 2021 update

“…Consequently, the in vitro culture of any intact human preimplantation embryo beyond 14 days or formation of the primitive streak (whichever occurs first) is now removed from Category 3. Instead, all research involving culture of intact human embryos is subject to Category 2 review, but balancing the potential value of this research with the ethical and societal concerns raised by it and taking into account the social responsibility to be transparent throughout the process, the guidelines recommend that, before a committee responsible for the specialized scientific and ethics review process may even consider applications for human embryo research beyond formation of the primitive streak or 14 days, national academies of science, academic societies, funders, and regulators should lead public conversations on the scientific significance as well as the societal, moral, ethical, and policy issues raised by allowing such research (Recommendation 2.2.2.1, Matthews et al., 2021 ). This public dialog should help provide guidance on what types of experiments might prove permissible.…”

新興人體胚胎研究技術、 十四天規則和胚胎的特殊地位

“…While some scholars suggest that the 14-day limit is arbitrary with no philosophical significance, both the US and UK commissions chose this point for several reasons (Hyun et al 2016 andMatthews et al 2021a). Fourteen days post-fertilization corresponds to the development of the primitive streak, which is easily visible under a microscope and one of the first significant signs of embryo organization (US DHEW 1979a;Warnock 1984).…”

“…Ethicist LeRoy Walters, who was involved in the preparation of the 1979 US report, believed that the 14-day date was also a safe choice, because it was far beyond researchers' ability to grow human embryos in 1978, such that the limit did not restrict research in actuality (Webster and McEwen 2016;Matthews et al 2021a). Scientists' ability to study early human embryo development in vitro has, until recently, been limited to the time the implantation stage begins (between days five and seven), which is also when an IVF egg would be implanted.…”

“…The diversity and plurality of societal views within and between countries highlights challenges finding a new scientific consensus for human embryo research. This plurality also suggests that public and stakeholder engagement would be necessary in developing new policies (Matthews et al 2021a). For examples on how public and stakeholder engagement could look, one only needs to look at how the US and UK reports on IVF were developed.…”

“…Prior to 2016, the 14-day rule functioned more as a theoretical boundary than as a practical limitation on research; even the most promising culture conditions could only maintain a human embryo through nine days of development (Matthews et al 2021a). Beyond the initial 2016 publications research on human embryos that reached 14 days in culture, research in 2019 and 2021 described the in vitro culture of monkey embryos up to 20 days post-fertilization and the development of an ex utero culture system capable of supporting mouse embryos through organ development (Niu et al 2019;Aguilera-Castejon et al 2021).…”