Scientists reject human cloning, support production of stem cells

Academy report comes amid Bush council talks

Senate to consider issue

January 19, 2002|By Jonathan Bor | Jonathan Bor,SUN STAFF

A prominent scientific panel urged a nationwide ban yesterday on the cloning of human beings but supported "therapeutic cloning" to produce stem cells for treatment of life-threatening diseases.

The panel, convened by the National Academy of Sciences, joined the debate as the ethically charged issue came before a presidential bioethics council and simmered on Capitol Hill.

In the six years since the birth of Dolly the sheep, the first cloned mammal, experiments that have produced cloned pigs, goats and cows have shown the procedure to be dangerous to both mother and offspring, the panel said.

Many of the cloned animals died in the womb, and survivors suffered such defects as lung, kidney and heart problems as well as brain damage, joint abnormalities and unusual weight gain. Last week, the panel noted, the Scottish scientists who produced Dolly reported that she was prematurely afflicted with arthritis.

"Human reproductive cloning should not now be practiced," said Irving Weissman, the panel chairman who is a professor of biology at Stanford University. "It is dangerous and likely to fail."

Such a ban should carry criminal penalties, the group said. The panel urged that the safety of reproductive cloning be re-evaluated every five years.

Weissman, however, said the panel would not support a ban on therapeutic cloning - the cloning of embryos to produce stem cells - because it holds the potential to cure ailments ranging from heart disease to diabetes.

The group said therapeutic cloning is safe because it does not involve the implantation of a fertilized egg into a woman's uterus. While an early-stage embryo would be created, it would be destroyed once it produced stem cells that could be harvested. Stem cells are precursors to all specialized cells in the human body.

The group made clear that it did not consider the moral and religious issues, such as when life begins and whether an embryo should be produced only to be destroyed. Instead, its mission was to evaluate scientific and safety issues.

Its recommendations are more permissive than the position taken by President Bush and the House of Representatives, which passed a bill last year that would ban all forms of cloning.

As the group issued its report at a Washington news briefing, the President's Council of Bioethics delved into the ethically charged issue on its second day of deliberations.

In a nationally televised appearance last summer, Bush said he was opposed to human cloning for any purposes. On Thursday, he asked his bioethics panel to be the "conscience of the country" and to guide him through the "nuance and subtlety" of cloning.

The president's council is headed by Dr. Leon Kass, a University of Chicago bioethicist who has written papers opposing cloning. It also includes two professors from Johns Hopkins University: Dr. Paul McHugh, the former chief of psychiatry, and Francis Fukuyama, a professor of political economy at the School of Advanced International Studies.

Meanwhile, the Senate is expected soon to consider the House legislation, though there appears greater Senate support for a bill that would leave room for therapeutic cloning.

So far, no human clones have been produced, though three scientists told the panel last fall that they intended to do so.

In reproductive cloning, scientists produce a genetic copy of an animal by extracting the genetic material from one of its cells and implanting it into an egg taken from a "donor" animal. Next, they stimulate the egg to start dividing - in effect, to behave as if it has been fertilized by sperm. When it reaches an early stage of development, the egg is implanted into an animal's womb.

In therapeutic cloning, the egg is kept alive for several days, the time it takes for it to produce stem cells.

Dr. Mark Siegler, a panel member, said he rejected the "slippery slope" argument - that permitting research into therapeutic cloning would inevitably lead to abuses, such as the production of cloned humans.

Dr. John Gearhart, a Johns Hopkins embryologist who was not on the committee, said he agreed with the panel's recommendations. But he feared that Congress and the administration would ignore the panel's recommendations, as it has many reports produced by the academy.

The National Academy of Sciences is a private organization that advises the government on scientific and technical issues.

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