How cloning stacks up

Ten years ago this month, a ewe at a quiet research facility just outside Edinburgh, Scotland, gave birth to a lamb, known then as 6LL3. Seven months later, 6LL3 stepped onto the international stage with a more personable name as the most famous sheep of all time: Dolly, the first cloned mammal. She was the product of inserting a cell from an adult sheep's udder into a sheep egg from which the nucleus had been removed, then placing it in a ewe to develop.

Dolly changed the public's idea of what biotechnology might do and immediately posed the question: Can human clones be far behind?

"Dolly was important as a symbol of science gone out of control," says Arthur Caplan, director of the Center for Bioethics at the University of Pennsylvania. "People were very afraid of cloning and what it might mean in terms of genetic engineering."

A decade later, those concerns and speculations have cooled. Cloning, it turns out, is a difficult proposition. Dolly was the sole survivor among 277 attempts to clone a sheep. Human cloning has proved elusive. Progress in cloning for research and medical purposes was hit hard late last year when an apparent breakthrough by South Korean researcher Hwang Woo-Suk, who claimed to have created human embryonic stem cells through cloning, was exposed as a fraud.

Cloning to reproduce a human being is now seen almost universally as too dangerous to consider. And animal cloning hasn't attained many of the goals expected a decade ago. Still, at least 15 mammals have been cloned (though no primates) and research continues.

What will the next 10 years bring? Here's what several close observers say:

"We spent an inordinate amount of time" arguing over human reproductive cloning 10 years ago, but "I don't think that's going to wind up being a very important issue 10 years from now." Dr. Caplan says. "I think the last 10 years have shown that cloning is a difficult process to control, often goes wrong, and that many of the reasons it goes wrong are probably inextricably tied up to the cloning process itself. I think that will pretty well seal the fate of cloning to make human beings. It will be understood that the price will be too high."

In a 2001 paper in the journal Science, Ian Wilmut, the lead researcher on the Dolly project, and Rudolf Jaenisch, a biologist and biomedical researcher at the Massachusetts Institute of Technology, wrote that human reproductive cloning was inherently dangerous and would always leave deformities in the clones.

"You cannot make normal clones. The ones that survive will just be less abnormal than the ones that die early," Dr. Jaenisch says today. "There has been no progress – none – in the last six years in making cloning more safe." For human reproduction, cloning "is totally out of the question."

Some 50 countries (though not the United States) have passed laws or issued regulations against cloning to make humans. That reproductive cloning is so widely condemned "even if only on narrow safety grounds" shows that "some lines can be drawn" past which science won't go, says Marcy Darnovsky, associate executive director of the Center for Genetics and Society in Oakland, Calif., a nonprofit interested in the public policy implications of genetic manipulation.

The goal of cloning early-stage human embryos to produce stem cells for use in research, and eventually to treat diseases, is likely to remain controversial. Those who see this research as destroying human life and those who do not regard these blastocysts (embryos in their very early stages) as human life have found little middle ground.

The battle is between "those who see this as the first step to a Brave New World and those of us who see this as a legitimate ... step toward regenerative medicine and all the benefits that can accrue" from that, says James Hughes, a sociologist and executive director of the Institute for Ethics and Emerging Technologies in Hartford, Conn. The group promotes the use of biotechnology to expand human capacities.

Bioethicist Caplan expects that one or more groups of scientists, perhaps outside the US, will do "what the Koreans said they did" and clone human stem cells. They'll be "useful in the laboratory, but we still won't be in a position to see cures coming from cloned human stem cell lines" in the next decade, he predicts.

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