Should the 14-day rule for embryo research become the 28-day rule?

In this commentary, the authors argue that it is time to consider if the 14-day rule can be extended to 28 days. They provide a list of arguments in favor of such an extension, including the opportunities to open up the “blackbox” of embryo development, increased knowledge about embryonic development and improvement of IVF procedures and the study of “synthetic” or stem cell-based embryos. Regarding ethical reasoning for the 14-day rule, they make several arguments. First, embryos used for research would not be used for attempting pregnancy and would be destroyed anyway eventually, so destroying at 14 or 28 days should make no difference. Second, embryos at 28 days do not experience sentience, pain or suffering. Third, slippery slope arguments are about regulation and policy, not necessarily about embryo culture research itself. The authors also assert the importance of a “reproductive Asilomar” and the need to involve the public and conduct consultations in embryo research decision-making.