A report issued 18 September by the American Association for the Advancement of Science (AAAS, publisher of Science) has called for a total moratorium on attempts to cure genetic diseases by altering the genome in ways that would be passed from one generation to the next. Human germ line gene therapy--and possibly some techniques in use today--would be unsafe and unethical, the report concludes. And it urges the government to create an independent panel to monitor public and private research and prevent such risky experiments.
In preparing the report, ethicists Mark Frankel and Audrey Chapman of the AAAS staff in Washington, D.C., consulted for 2 years with a score of advisers in gene therapy, ethics, sociology, and theology. They found wide support for a moratorium on germ line gene therapy. But they went further, proposing a moratorium on therapies that might change human DNA accidentally, including methods used by some reproductive medicine clinics.
The DNA editing methods that make it possible to revise mammalian genomes are "developing impressively," said Theodore Friedmann, director of the gene therapy program at the University of California, San Diego, and adviser to the AAAS authors. It would be exciting to try to "fix" genetic diseases by editing the human genome, Friedmann said, but he is convinced that the risks of injury--not just to the individuals immediately affected but to future generations--outweigh the potential benefits.
The AAAS report reflects this concern, although it supports expanded basic research in this field as well as clinical gene therapy for cells other than sperm and eggs. The report proposes that a national group of experts and lay people be established to keep tabs on the field, particularly on private firms that might try to sell genetic "enhancement" therapies offering to improve the beauty, brains, or brawn of children.
At present, no public or private labs are proposing to do germ line gene therapy. But the report questions therapies used by reproductive medicine clinics, including one in which cytoplasm from a donor egg--complete with mitochondria--is injected into an egg slated for fertilization. A child born from this process may inherit mitochondrial DNA from both eggs. The AAAS report classifies this as a type of "inheritable genetic modification" and argues that it should not be done at present.
Jacques Cohen of St. Barnabas Medical Center in Livingston, New Jersey, which developed the technique, agrees that it is "highly experimental." But he argues that it is "an incredible stretch" to classify it as germ line gene therapy. He says he has found no harmful effects from the technique, which has enabled infertile women to give birth to healthy babies--15 at last count.