The Magazine

The False Promise of "Therapeutic" Cloning

Moral considerations aside, human cloning is not going to lead to useful medical treatments.

Mar 11, 2002, Vol. 7, No. 25 • By WESLEY J. SMITH
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THE SENATE will shortly take up one of the most pressing moral, ethical, and scientific issues of our time: the Brownback proposal to outlaw human cloning. Two alternative proposals would ban only "reproductive cloning," which would mean explicitly legalizing human cloning but not the implantation of a clone embryo into a womb. Pro-cloners are willing for the most part to outlaw reproductive cloning (for now) because it isn't safe and it gives the appearance of a reasonable compromise. But they oppose a ban on cloning for research and experimentation--euphemistically known as "therapeutic cloning"--arguing that such a cloning license is necessary to the development of future medical treatments for terrible human ailments.

The case against cloning, including therapeutic cloning, has mainly been argued on grounds of morality. Opponents have warned that creating embryos through cloning for the purpose of research (with the full intention of destroying them later) is a breathtakingly radical enterprise. For the first time in history, human lives will be created for the explicit purpose of exploitation. Such considerations have led activist Jeremy Rifkin to opine that the cloning debate is to the 21st century what the slavery debate was to the 19th.

Unfortunately, we live in a time of widespread and extreme non-judgmentalism, an era when many Americans simply do not respond to moral arguments in public policy debates. For these folk, what counts is not right versus wrong, but whether it will or won't work--in a word, utility.

Does this mean that the public policy amoralists among us must end up by default on the pro-cloning side? Not at all. There is increasing evidence that therapies based on cloned embryo cells would be so difficult and expensive to develop and so utterly impractical to bring to the bedside, that the pie-in-the-sky promises which fuel the pro-cloning side of the debate are unlikely to materialize. Not only is human cloning immoral but it may have negative utility--in other words, attempting to develop human cloning technologies for therapeutic use may drain resources and personnel from more useful and practical therapies.

To understand why therapeutic cloning fails the utility test, we must take a quick look at the significant difficulties facing embryonic stem cell research. Embryonic stem cell researchers hope to create medical treatments that would use undifferentiated cells--known generically as stem cells--extracted from 5-to-7-day-old embryos known as blastocysts. During natural gestation, these stem cells eventually "differentiate," that is, they transform into bone, neurons, muscle, organs, blood--indeed, all of the more than 200 different tissue types in the body. Researchers hope to learn how to harness this ability by extracting stem cells from embryos, transforming them into specific tissues, and then injecting the tissues into patients to treat medical ailments.

In their enthusiasm for embryonic stem cells--and in an effort to assure ample funding for the research--some advocates have all but promised that such therapies are just around the corner. But that isn't even close to being true.

Writing in the scientific research journal Stem Cells, editor in chief (and advocate of embryonic stem cell research) Curt I. Civin admitted that "scientists have exaggerated the immediacy of the prospects of clinical therapies using stem cells." Moreover, Civin believes that "clinical application" of stem cell therapies is actually "a long way off." Why? Primarily two reasons: First, embryonic cells may cause tumors in patients; and, second, the body may reject embryonic tissues in the same way the immune system rejects transplanted organs.

A recent experiment involving rats, reported in the January 8, 2002, Proceedings of the National Academy of Sciences, illustrates the tumor problem. Researchers at Harvard Medical School and McLean Hospital in Belmont, Massachusetts, injected mouse embryonic stem cells into rats to relieve Parkinson's disease-like symptoms. Of the 25 rats receiving the embryonic stem cells, 14 showed modest improvement, 6 showed no benefit, and 5 died of brain tumors caused by the stem cells. In other words, the therapy actually killed 20 percent of the recipients of the embryonic stem cell therapy. And this occurred even though researchers tried mightily to prevent tumor formation by injecting only 1 percent of the number of such cells that have been used in other experiments that led to tumor deaths. It is becoming clear that overcoming the problem of tumor formation--if it can be done--will be a very difficult, time-consuming, and expensive undertaking.