Michel Revel, a Professor in the Molecular Genetics Department of the Weizmann Institute of Science in Rehovot, Israel, is a member of UNESCO's International Bioethics Committee, which drafted the Universal Declaration on the Human Genome and Human Rights. Revel was Israel's delegate to the General Conference of UNESCO, which adopted a revised text of the declaration in November.

"The more knowledge, the more distress," says the Talmud. How true that seems for the field of genetics; As soon as advances in laboratory animals we announced, the news is used to forecast a revolution in human reproduction: Let's make genetically ideal babies, let's clone human copies, let's make headless fetuses for transplantable spare parts. Biology' has become a convenient target for moralists and politicians who condemn science and are eager to ban new experimentation.

"To benefit from scientific advancement" is a basic human right defined by the United Nations. Exercising this right implies defining the limits of the permissible and weighing the moral conditions of action; Ethics committees ought to explain the potential benefits of scientific applications and create guidelines for their use, rather than try to have them outlawed upfront.

Fear of eugenics and of illusory social manipulations has led several governments to outlaw applications of cloning to humans. In a revised text of its Universal Declaration on the Human Genome and Human Rights adopted at the organization's General Conference on November 12, UNESCO added a statement defining cloning as "contrary to human dignity" (Article 11).

I believe that one could have adopted another position. Indeed, ethicists who drafted the original UNESCO declaration meant to ensure that application of any genetic practice to human beings be developed with respect for the rights and dignity of individuals. They also meant to ensure that mankind would not be deprived of benefits such progress might bring if applied within the bioethical guidelines outlined eloquently in the rest of the declaration. For these reasons, several delegations proposed not to rush in condemning any particular technique, including cloning.

It may be worth remembering that after the first human in vitro fertilization in ~978, "creating a human being in a test tube" was criticized as undignified and offensive to human love. Since then, assisted reproduction has alleviated distress for thousands of parents. Speculating that it may be achieved safely, cloning could be just another form of assisted reproduction. Fertilization by an adult cell nucleus- the essence of cloning- may be invaluable for a man and a woman who are both sterile and desire a biological child, or a religious couple who consider an extramaritally donated sperm or egg adulterous.

Reproduction by cloning may also hold a solution when one partner carries a severe hereditary disease, allowing the other partner to contribute his or her genome to their offspring. This is why some countries, including Israel, consider it sufficient to strictly regulate rather than ban cloning research.

Hoping to make an exact replica of oneself by cloning is unrealistic. Cloned human beings would resemble each other no more than monozygotic twins. Cognitive abilities are patterned by education and environment as well as genetics. Genetic identity is an illusion; cloned animals differ in their hair color patterns. The immune system of each human being is different, and So may be brain wiring. The surrogate egg and its mitochondrial DNA exert a maternal influence on the development, as does the pregnant mother's nutritional behavior.

Obviously, there can be no substitute for mixing human genes through sexual reproduction and for the diversity that underlies the unity of the human species. The key to avoiding megalomaniac attempts to improve racial human subgroups or produce human beings with "useful traits" is to ensure that the technology serves only the needs of the individual and not goals desired by society. It must never be used except for therapeutic purposes, respecting the rights, autonomy, and dignity of the mother, of the donor, and of the child to be born. The rights and wrongs of cloning, or for that matter of any genetic manipulation, should be decided on a case-by-case basis.

Cloning research ought to be allowed to continue within agreed guidelines because it entails benefits that should not be scrapped outright because of perceived risks. Cloning may help overcome present hazards of graft procedures. Embryonic cells could be taken from cloned embryos prior to implantation into the uterus, and cultured to form tissues of pancreatic cells to treat diabetes, or brain nerve cells that could be genetically engineered to treat Parkinson's or other neurodegenerative diseases.

Whether producing embryos for such purposes is ethical will depend on views toward early embryonic life, as well as on whether saving an existing human life justifies ending that of embryos. Christianity sanctifies life from fertilization, while Judaism and Islam consider the embryo to acquire human characteristics only after 40 days. Scientific guidelines allow embryos to be grown in culture for 14 days. The ethical discussion should respect individual religions and philosophies.

The lack of consensus on what makes an embryo into a human being will affect the debate on headless embryos that could provide formed organs for grafts. Lethal fetal malformations have been recognized since antiquity, and moralists have considered fetuses with no identifiable head and chest as non humans. whether saving a human life by willfully producing such fetal abortuses is compatible with human dignity will be debated -and ought to be- considering that a woman will have to bear the fetus. At the same time, the unavailability of organs is becoming a major death factor that will worsen unless scientists successfully culture fully formed organs. Today's organ traffic could appear to many a more dangerous peril than producing one's own cloned embryo for autograft.
Ethics should weigh the if- of the individual to benefit from scientific advancement against the risks, and strictly regulate rather than condemn. Demonization of science and upfront banning of potential new technologies is not a dignified human answer.