APPENDIX E:

PLEDGE BY THE SOCIETY FOR DEVELOPMENTAL BIOLOGY (SDB) TO SUPPORT MORATORIUM ON CLONING OF A HUMAN BEING

SOCIETY FOR DEVELOPMENTAL BIOLOGY

Voluntary Moratorium On Cloning Human Beings

Resolved: The Society for Developmental Biology declares a voluntary five-year moratorium on cloning human beings, where "cloning human beings" is defined as the duplication of an existing or previously existing human being by transferring the nucleus of a differentiated, somatic cell into an enucleated human oocyte, and implanting the resulting product for intrauterine gestation and subsequent birth.

Background Overview: The recent demonstration that the nucleus of an adult sheep cell can be completely reprogrammed by the oocyte cytoplasm to generate a new adult sheep is exciting to developmental biologists because it demonstrates that the genetic information in mammals can remain intact in a differentiated adult somatic cell. In other words, nuclei of adult somatic cells can be totipotent and capable of generating an entire adult organism. This had long been suspected from studies in amphibian embryos, but was not proved for any animal until the recent sheep study by Wilmut and co-workers (Nature 385:810-13, 1997).

Basic Science Issues: The demonstration of totipotency in an adult mammalian somatic nucleus compels us to re-examine the process of cell differentiation. Specifically, it is important to study the means by which cells achieve a stable differentiated state and the extent to which differentiation can be altered by changing the cytoplasmic environment of adult nuclei. It is also important to identify the cytoplasmic factors that regulate differentiation in somatic cells and confer totipotency in oocytes.

Human Health and Biotechnology Applications: This demonstration of totipotency in an adult nucleus provides a major impetus to reprogram adult human cells so they can be used in cell-based therapies for human diseases. Thus, a full understanding of how cytoplasmic factors can reprogram adult nuclei holds great hope for developing novel strategies for repair and regeneration of human tissues, for example in treating diabetes, cancer and neurodegenerative diseases.

Application to Cloning Human Beings: The totipotency of adult nuclei could theoretically be applied to clone human beings, but there are major practical and ethical objections to carrying out such an act. First, based on current knowledge, the efficiency of embryonic development after nuclear transfer is so low, and the chance of abnormal offspring so high, that experimentation of this sort on humans is unsafe at this time. Thus, any possible therapeutic objectives of cloning human beings would be achieved at great risk to the offspring. Moreover, the deliberate generation of cloned human beings could infringe upon the dignity and integrity of human individuals. In response to these ethical concerns, federal and state representatives have introduced legislation intended to block cloning of human beings. However, imprecise or misused technical language in some of these resolutions could deter valuable research.

Voluntary Moratorium on Cloning Human Beings: As developmental biologists, we wish to encourage important new research on cell differentiation and nuclear-cytoplasmic interactions in laboratory animals, including mammals, in order to fully understand the implications of nuclear totipotency. We expect that further research using human cells will also be necessary to secure the benefits of insights from animal cloning and nuclear transfer as applied to human health. By contrast, we would regard cloning a human being as an unethical and reprehensible act.

Historical precedent (with recombinant DNA technology) indicates that a voluntary moratorium is an effective means of preventing procedures that are potentially harmful or unsafe for humans. Therefore, the membership of the Society for Developmental Biology declares a voluntary moratorium on cloning human beings. Members of the Society have no intention of cloning human beings, where this act is defined as the duplication of an existing or previously-existing human being by transferring the nucleus of a differentiated, somatic cell into an enucleated human oocyte, and implanting the resulting product for intrauterine gestation and subsequent birth. In accord with the recommendations by the National Bioethics Advisory Commission, this moratorium shall be in effect for a period of five years, with subsequent reconsideration for possible extension.