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Therapeutic Dreaming

The False Promise of Experimental Cloning Original Article

POLLS SHOW that most Americans want to ban all human cloning. President Bush is eager to sign such a measure into law. The House has twice enacted a strong legal prohibition with wide, bipartisan votes. But cloning advocates have so far blocked passage of a ban in the Senate (Brownback/Landrieu) by asserting that “therapeutic cloning” might someday provide stem cell treatments for horrible illnesses such as Parkinson’s and multiple sclerosis.
According to the Biotechnology Industry Organization, the biotech industry’s lobbying arm, here’s how therapeutic cloning would work:

Suppose a middle-aged man suffers a serious heart attack while hiking in a remote part of a National Park. By the time he reaches the hospital, only a third of his heart is still working, and it is unlikely he will be able to return to his formerly active life. He provides scientists a small sample of skin cells. Technicians remove the genetic material from the cells and inject it into donated human eggs from which the chromosomes have been removed. These altered eggs [actually, cloned embryos] will yield stem cells that are able to form heart muscle cells. Since they are a perfect genetic match for the patient, these cells can be transplanted into his heart without causing his immune system to reject them. They grow and replace the cells lost during the heart attack, returning him to health and strength.

This scenario is typical of the hype that has pervaded discussions of therapeutic cloning over the last few years. But now, cold reality is setting in. Biotech researchers and cloning advocates are admitting difficulties in their professional journals, if not yet in the popular press, that make therapeutic cloning look more like a pipe dream than a realistic hope.

Consider a paper by Peter Mombaerts of Rockefeller University, “Therapeutic Cloning in the Mouse,” just published by the National Academy of Sciences (NAS). Mombaerts has been investigating therapeutic cloning techniques in mice. It has been tough going. Of these efforts, he sadly reports, “The efficiency, or perhaps better, the lack of efficiency thereof, is remarkably consistent.” It takes about 100 tries to obtain one viable cloned mouse embryonic stem cell line.

Mombaerts notes that creating human cloned embryos using “nuclear transfer is unlikely to be much more efficient” than it is in mice, especially given that “the efficiency of nuclear transfer has not increased over the years in any of the mammalian species cloned.” Nuclear transfer, more precisely somatic cell nuclear transfer (SCNT), is the same procedure used to create Dolly the sheep. The nucleus from an egg is removed and replaced with the nucleus from a clone donor’s somatic cell, such as a skin cell. The modified egg is stimulated with an electric current. If the cloning “works,” a cloned embryo is created that then develops just like a naturally created embryo.

Given the significant difficulties researchers have already had, deriving cloned embryonic stem cell lines is likely to be far less efficient in humans than it has been in mice (assuming that it can be accomplished at all).

This is big news and let’s hope senators are paying attention. If they are, it should sink the rival to Brownback/Landrieu, Orrin Hatch and Dianne Feinstein’s cynically misnamed Human Cloning Ban and Stem Cell Research Protection Act of 2003, which would not outlaw human cloning at all but would explicitly legalize it. If it takes 100 or more tries to make a single human cloned embryonic stem cell line, therapeutic cloning is all but doomed as a viable future medical treatment.

It’s a simple matter of resources. There are more than 100 million Americans, according to the National Academy of Sciences, who might one day benefit from therapeutic cloning if all the high hopes for it panned out. Each therapeutic cloning attempt would require one human egg. If it takes one hundred tries per patient for a cloned embryonic stem cell line to be successfully created, therapeutic cloning will never become a widely available therapy in medicine’s armamentarium because there will never be enough eggs.

Do the math: One hundred million patients at 100 eggs each would mean that biotechnologists would need access to at least 10 billion eggs just to treat the Americans the NAS has identified as having degenerative conditions that might respond positively to stem cell therapy. Even if we decided to strictly ration therapeutic cloning to, say, the sickest 100,000 patients, you would still need 10 million eggs! Even this strict rationing would require one million women of childbearing age to submit to egg extraction. These numbers are mind-boggling.

Then there is the cost. At present, young women sell their eggs for use in fertility treatments at a rate, Mombaerts reports, of $1,000-$2,000 apiece. This means that the cost of obtaining one cloned stem cell line—never mind the expenses associated with doctors, hospitals, and laboratories—would run in the neighborhood of $100,000-$200,000, “a prohibitively high sum” that Mombaerts expects “will impede the widespread application of this technology in its present form.” And if you think this exorbitant price tag is high, consider the cost when egg price hyperinflation is unleashed by the surge in demand for eggs to be used in therapeutic cloning.

Put all of this together and it means that if human therapeutic cloning could ever be developed—a big if—it would either be very strictly rationed, or available only to the super rich. This is not what senators are being told when biotechnologists promise future miracle cures from therapeutic cloning for millions of their constituents.

Is there a way out of this egg dearth? Mombaert’s article suggested two potentialities, to which I add a horrific third:

  1. We could use animal eggs. Animal eggs are more readily available than human eggs, which would reduce the price of therapeutic cloning considerably. But using animal eggs would mean creating hybrid human/animal clones. I doubt the American people would stand for this violation of nature’s laws. (Mombaerts understates the case when he admits, “The idea of generating embryos with mixed human/animal properties, even transiently, is offensive to many people.”) From a practical standpoint, the stem cells and indeed all tissues that would be extracted from such human/animal hybrids would contain nonhuman mitochondrial DNA. This could easily stimulate an auto-immune response or risk mitochondrial diseases in patients.
  2. We might be able to learn how to transform embryonic stem cells taken from fertilized embryos into fully formed human eggs. This has been done in mice, but it will take many years to determine whether it can also be done with humans. But even if researchers learn how to morph stem cells into eggs, that does not mean they would be ready for use in cloning. Researchers would also have to ensure that they were not genetically defective and learn how to mature these eggs to the point where they would be usable for cloning. And even if they were able to learn how to do that, considering the huge number of eggs that would have to be produced in this way for therapeutic cloning to become widely available, morphing eggs out of embryonic stem cells hardly seems a plausible answer to the implacable egg dearth.
  3. We could take the ovaries from female fetuses destroyed in late-term abortions, and maintain them in the hope of harvesting and maturing their eggs. I know this is revolting, but, sad to say, Dutch and Israeli researchers are already experimenting on this very thing with second and third trimester aborted fetuses, toward the goal of obtaining eggs for use in infertility treatments. Not only does this macabre research open the possibility that an aborted baby girl could become a mother, but if the procedure were perfected, it could result in aborted late-term female fetuses becoming a prime source of eggs for use in human cloning. As if that weren’t troubling enough, the abortions of these female fetuses would have to be done in a way that did not damage their nascent ovaries, perhaps providing utilitarian impetus for the odious partial-birth abortion technique.

To pursue therapeutic cloning is to chase a mirage. On the other hand, adult stem cell research, a practical and moral alternative to therapeutic cloning, is already in human trials and moving ahead at tremendous speed. It was just announced, for example, that four out of five seriously ill human heart patients in a trial in Brazil no longer need heart transplants after being treated by their own bone marrow stem cells.

With all of the serious problems, both moral and practical, associated with human cloning, there is no longer any excuse for the current political impasse. The time has come for our senators to toss the Hatch/Feinstein phony cloning ban in the round file and pass the Brownback/Landrieu ban without further delay.

Wesley J. Smith, a senior fellow at the Discovery Institute, is writing a book about the science, morality, and business of human cloning.

Wesley J. Smith

Chair and Senior Fellow, Center on Human Exceptionalism
Wesley J. Smith is Chair and Senior Fellow at the Discovery Institute’s Center on Human Exceptionalism. Wesley is a contributor to National Review and is the author of 14 books, in recent years focusing on human dignity, liberty, and equality. Wesley has been recognized as one of America’s premier public intellectuals on bioethics by National Journal and has been honored by the Human Life Foundation as a “Great Defender of Life” for his work against suicide and euthanasia. Wesley’s most recent book is Culture of Death: The Age of “Do Harm” Medicine, a warning about the dangers to patients of the modern bioethics movement.