WITH THE SEQUENCING of the human genome and our increasing knowl-edge of the molecular mechanisms of basic cell functions, we are entering an era of rapid advance in the field of developmental biology. Current scientific interest in embryonic stem cells is a logical step in the progress of these studies and holds the hope of providing important research tools as well as possible therapeutic applications.

The ethical controversy surrounding cloning for biomedical research (CBR) 1 and human embryonic stem cell (ES cell) research arises from the fact that to obtain these cells living human embryos must be disaggregated and destroyed. Many Americans oppose such embryo destruction, believing that there is an implicit dignity and inviolability in the individual continuity of a human life from fertilization to natural death. Many others, however, believe that the benefits of advances in biomedical science outweigh these moral concerns.