The Future of Stem Cells

July 8, 2004 -- Stem cell research is one thing. Cloning human babies is another. Yet the two issues are so mixed up, we risk the worst of both worlds.

Research into stem cells may provide treatments for terrible medical ailments. The list includes Alzheimer's and Parkinson's diseases, cancer, and spinal paralysis. That's why Nancy Reagan, Michael J. Fox, and Christopher Reeve all are outspoken advocates.

There are all kinds of stem cells. But the ones from which we can learn the most are the cells that make up an early human embryo. They're formed in the first 14 days after a human egg is fertilized by sperm or when a human egg has its own DNA replaced by DNA from an adult cell.

Scientists call this latter technique somatic cell nuclear transfer or SCNT. It's also the first step in cloning. And there's the rub. If a SCNT-created embryo is implanted in a woman's womb, it might become a cloned baby genetically identical to the DNA donor. Does stem cell research necessarily put us on the slippery slope that leads to reproductive cloning?

No, argues Carol A. Tauer, PhD, of the Center for Bioethics at the University of Minnesota, Minneapolis. Writing in the July 10 issue of The Lancet, Tauer says that stem cell research and reproductive cloning are totally separate issues.

Mixing them up, she says, is a terrible mistake. On the one hand, fear of human cloning might shut the door on the promise of stem cell research. And on the other hand, the confusion makes it very hard to pass a law almost everybody wants: a ban on reproductive cloning.

"Although there is agreement that it is good to prohibit cloning for reproduction, there is no agreement on whether cloning should be prohibited for treatment research," Tauer tells WebMD. "When these two issues are put together, it makes it impossible to pass any laws."

Tauer advises the U.S. government -- and the U.N. -- to consider the issues separately.

"One thing should be done at a time," she says. "Congress should take cloning for reproduction -- on which there is wide agreement -- and get that passed. And then they should look separately on the issue of whether federal funding should be extended to stem cells and cloning for research. People on both sides may not want to agree with me. But I think if we agree on one thing, why not take care of that -- both in the U.S. and also at the level of the U.N. -- and then look at other issues."

Deliberate Confusion

That's not likely to happen, says Arthur Caplan, PhD, director of the center for bioethics at the University of Pennsylvania, Philadelphia.

"Of course the issues should be separate," Caplan tells WebMD. "But as sensible as this seems to be, the critics of stem cell research see that to split the issues is to lose the debate. Many of those who support a total ban on cloning would back off if reproductive cloning were off the table. It is specifically mixed up by those who are critical of stem cell research. They want to fuzz the line because that is their best bet to ban everything."