BEFORE I WAS AN EMBRYO, I WAS A PREEMBRYO - OR WAS I

Issues surrounding human embryos are poignant and profound. Should res earch be conducted on them? Should they be discarded? Should they be d onated to infertile couples? The Warnock Report1 was a landmark in pro viding guidelines limiting experimentation on human embryos to the fir st 14 days after fertilization, at which time implantation of the embr yo is complete and the primitive streak has appeared.2 However, these embryological features were not considered sufficiently distinctive to bestow upon this 14-day period a separate classification. This situat ion changed when, in 1986, Anne McLaren suggested the use of the terms 'pre-embryo' or 'conceptus' to designat ''the entire product of the f ertilized egg up to the end of the implantation stage'' and the term ' embryo' for ''that small part of the pre-embryo or conceptus, first di stinguishable at the primitive streak stage, that later develops into the foetus.''3 In this paper we look critically at the term 'pre-embry o', and we shall present the case for an alternative set of terms, nam ely, embryo-placenta and embryo-fetus. We consider this latter to be b iologically-based terminology, that does not have any connotation of r estricted moral value as the term pre-embryo does for some.