How and Why to Replace the 14-Day Rule

Purpose of Review The '14-day rule', which limits research on human embryos to the first 14 days after fertilisation, has long been a pillar of regulation in this contested area. Recently, advances in developmental biology have led to calls to rethink the rule and its application. In this paper, I address the question of whether the 14-day rule should be replaced and, if so, how. Recent Findings The two lines of research that have prompted this question are new techniques enabling culture of embryos at least up to 14 days and patterning experiments with pluripotent cells suggesting that they might form embryo-like structures. I consider each of these in relation to the foundations and function of the rule to examine whether they warrant change. Summary I argue that the 14-day rule for embryo research should be open to change, but that this possibility must be addressed through early and thorough discussion involving a wide range of publics and other stakeholders.