Cloning: Where Do You Draw The Line?

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But even some pro-life lawmakers don't want fears about cloning to stop other kinds of stem-cell research that do not entail the manufacture of new embryos. Many have been relying on a kind of moral escape hatch: the fact that every year there are tens of thousands of frozen embryos left over from fertility treatments in clinics around the country. National Institutes of Health guidelines say it is O.K. to do research on cells from such embryos, most of which would be destroyed anyway; but it is wrong to create an embryo solely for the purpose of harvesting its cells, which can occur in some types of therapeutic cloning. That is the guideline stem-cell proponents are urging Bush to embrace and the one that made it impossible for many moderates, as well as conservatives, to accept the Greenwood proposal, which would violate it.

But if lawmakers were willing to make small moral compromises in hopes of progress toward a cure, why not make a bigger compromise if it promised a miracle? All embryonic-stem-cell research is basically about growing new, healthy tissue to replace the damaged heart muscle in a cardiac patient, for example, or the nerves of a paralyzed person. Researchers believe that stem cells harvested from embryos derived from your own cells may be the most valuable of all because they would provide a perfect genetic match: grow them into new liver or brain cells, and there is probably little chance of rejection. You would never need to actually clone a full-grown baby, they argue; just create the embryo, harvest the stem cells and learn how to make them grow into whatever replacement tissue you need.

Researchers at Advanced Cell Technology, a Massachusetts biotech firm that had announced its efforts to clone embryos, hold out the possibility that within 15 years, scientists will be able to reprogram human cells without having to rely on human eggs and embryos at all. They call it cellular DNA remodeling. By studying cloning, scientists hope to figure out how to take a full-grown adult cell, restart the clock and transform it into entirely new tissue. Then when you have a heart attack, doctors will take one of your skin cells, remodel it into heart tissue and repair all the damaged parts of the heart with new, healthy cells. Such direct remodeling could heal bone breaks, trauma, burns, kidney malfunction and on and on.

This research will proceed much faster, scientists argue, if they are allowed to create embryos--and the Weldon bill would shut it all down. "If therapeutic cloning research is allowed to proceed, it will lead to a wholly new medicine in this century," argues Dartmouth religion professor Ronald Green, who chairs the ethics board at Advanced Cell Technology. But a full ban "will drive all this research underground or offshore, depriving us of the medical benefits of this research for no net gain." The Weldon ban even prohibits the import of therapies created outside the U.S. from cloned embryos, which raises the prospect of a cure for cancer that is available in Europe but illegal in the U.S.

How can we be so squeamish about doing research on cloned embryonic cells, New York Democrat Jerrold Nadler demanded of his House colleagues, when "we permit abortion? We permit in-vitro fertilization, which creates nine or 10 embryos, of which all but one will be destroyed. We must not say to millions of sick or injured human beings, 'Go ahead and die, stay paralyzed, because we believe the blastocyst, the clump of cells, is more important than you are.'" But advocates of the ban say the promise of therapeutic cloning has been oversold. By the time researchers actually perfect the technique, they may have solved problems like organ rejection through some other means. "People were holding up the prospect of growing your own liver as something that could happen tomorrow or very soon," argues Oregon Democrat David Wu, "and that is clearly not the case."

For lawmakers like Wu, who support embryonic-stem-cell research as long as it does not involve intentionally manufacturing embryos, this was an important place to draw the line. It's fine to pursue cloning technology with animals or adult DNA and tissue cultures, but not to create embryos for experimentation. Setting that limit might slow progress, but that might be a good thing if it gives everyone a chance to reflect on matters this complex. "This is not about the limits of human technology," Wu says. "It is about the limits of human wisdom."

It is also about the limits of law. What good is a partial ban on cloning if it cannot be enforced? Once embryos are produced for research and stockpiled in labs, lawmakers warned, it's hard to control how they are used. Even under Greenwood, which would subject private labs to some government oversight, there would be no knowing for certain whether scientists were violating the law against actually implanting a cloned embryo in a surrogate mother. And if someone found out? "No government agency is going to compel a woman to abort the clone," argued University of Chicago medical ethicist Leon Kass at hearings earlier this summer.