More MS news articles for Sep 2001

Ethical Limits on Stem Cell Research

September 8, 2001
Nearly a century ago, in the preface to his play "The Doctor's Dilemma," George Bernard Shaw laid down a simple rule that no medical researcher caught up in the current controversies over embryonic stem cells or therapeutic cloning would think to challenge.

Shaw, of course, put the matter in the usual outrageous way he employed to provoke thought. "No man," he wrote, "is allowed to put his mother into the stove because he desires to know how long an adult woman will survive at a temperature of 500° Fahrenheit, no matter how important or interesting that particular addition to the store of human knowledge may be."

And just to nail the point down, he added, "When a man says to Society, `May I torture my mother in pursuit of knowledge?' Society replies `No.' If he pleads, `What! Not even if I have a chance of finding out how to cure cancer by doing it?' Society still says, `Not even then.' "

Of course, researchers who recognize this passage as part of a polemic against vivisection may want to keep their distance from Shaw's well- known suspicions of medicine and medical practice.

And they would also want to respond, "But an embryo is not someone's mother, even if it could in principle become someone's mother, and to destroy it in extracting cells for research can hardly be compared to torture."

But they still would not disagree with the basic point. In fact, scientists and politicians urging more government financing of embryonic stem cell research and fewer government limits on it routinely insist that the promise of medical progress does not override all ethical limits.

The difficulty has been in establishing exactly where these research advocates would place those limits. If they reject fertilization as the place to draw a moral line, where would they draw it? And, just as important, why?

Not that these questions have gone completely unaddressed. While recognizing that embryonic development is a gradual process, some researchers, politicians and ethicists have highlighted certain milestones in that development as perhaps morally relevant.

One is the stage when embryos would normally implant in a uterus. Another occurs when embryonic cells are so committed to their eventual body parts that splitting into identical-twin embryos is no longer possible. A third is the roughly simultaneous appearance of the "primitive streak," indicating that twinning is no longer possible and also giving the embryo a new level of organization, presaging the development of organs and a nervous system.

All these "biological markers" occur after the period when embryos are destroyed by the extraction of stem cells, the issue now under debate. But those concerned about the long-range trajectory of embryonic research naturally wonder whether such markers, taken singly or in convergence, constitute rationally justifiable limits where society and science could agree in forcefully saying, "To this point human life can be treated as an experimental object or as raw material for therapy, to this point but no further, not even if a cure for cancer is in the offing."

In 1984, the committee that set the framework for Britain's regulation of human embryo research recommended limiting such research to 14 days after fertilization. So did the Human Embryo Research Panel that advised the National Institutes of Health in 1994.

Both committees placed heavy emphasis on the appearance of the primitive streak, but they were also influenced by the convergence of several other factors in the developmental process by the 14th day.

To be sure, proponents of protecting human life from the moment of fertilization are not convinced, and they can mount impressive criticisms of these later limits. But a deeper question lurks beneath the debate:

Are ethical limits, to which everyone gives lip service, really based on some inherent and morally significant quality of human life? Or are they strictly provisional dividing lines, like the movable rubber cones or wooden horses that are used to block off road work or parade routes, handy enough to allay anxiety and ward off conflict for now but easily shifted if the potential benefits of medical research so require?

Of course, physical facts alone do not dictate moral norms. People read physical facts through the lenses of values already held, and a kind of negotiating occurs between facts and values. Is this 5-day-old human embryo deserving only of the somewhat nebulous respect owed valuable blood and organs, or even past and future generations? Or is this embryo deserving of the entirely different, higher level of respect accorded the individual human being?

There is a great deal of difference between answering those questions by looking at the embryos themselves and answering them by some external criterion, like whether their destruction may benefit future diabetics or whether they are scheduled to be discarded anyway. It is the tendency to advance such external criteria as decisive that has reinforced the worry that, in the end, adding to the store of knowledge is the one fixed star of scientific and medical research and that, short of roasting mother, everything else is ultimately adjustable.

That worry agitates many serious people who do not otherwise find compelling the case for protecting blastocysts or frozen embryos but who recognize that the precedents established in embryonic stem cell research will have broad and long- lasting consequences for science and human reproduction.

There is no reason that this void in the ethical discussion cannot be filled. Congressional hearings could devote at least as much time to the ethical questions as to whether there are 64 or 24 embryonic stem cell lines usable for research.

Copyright 2001 The New York Times Company