Bioethics Blogs

SHEEFs, Sentience, and the 14-Day Rule

March 31, 2017

by Professor Bonnie Steinbock 

Embryo research, made possible by IVF, raised the question of the moral status of human embryos. Are human embryos human subjects, who are entitled to stringent protections? Or are they clumps of cells that can be used in research, so long as the permission of their creators is obtained?

Various commissions (Ethics Advisory Board, 1979; Warnock Commission, 1984; National Institutes of Health, 1994) considered this issue, and all arrived at a similar conclusion. Embryos are neither persons nor mere tissue, but a very early form of human life and, as such, entitled to special respect. Specifically, they all agreed on the 14-day rule, which specifies that experiments with human embryos must not let them develop beyond 14 days.

Fourteen days is when the primitive streak (PS), the precursor of the spine and nervous system, appears. This is important because of the connection between the nervous system and sentience, the ability to experience pain or pleasure. Sentience is regarded as morally relevant because causing pain is, in general, wrong. Kicking a can down the road is perfectly permissible, but it would be very wrong to do the same to a sentient guinea pig. On a sentience criterion, nonsentient beings do not have the moral standing that sentient beings do, and research on nonsentient embryos is morally acceptable.

Some argue that what makes it wrong to kill an embryo has nothing to do with sentience. Rather, the embryo is the earliest stage of a unique human being. If it would be wrong to kill a developed human, it is equally wrong to kill that same human being in its earliest stages.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.