Embryo experimentation: is there a case for moving beyond the ‘14-day rule’

Grant Castelyn
The author analyzes the main justifications provided by the Warnock committee for the 14-day limit of embryo research in vitro and finds them unconvincing; discussions about extending the limit must determine whether the limit was valid in the first place. The first objection is against the argument that individuation is necessary for moral status, since it can occur later than 14 days, and an individual entity is present before any twinning. The second objection is against neural development (the primitive streak), since the emergence of a Central Nervous System also occurs later than 14 days of embryo development. These objections do not mean that embryo research should be prohibited, since the author does not find the potential to become a human being as sufficient to grant moral status. As an alternative justification for the imposition of limits in embryo research, the author suggests that determining the limits of embryo culture could be based on indicators of precursors of sentience so that the embryo avoids suffering; these appear after 14 days.