Published March 1, 2006
Over the past few years, the debate over stem cells and cloning has grown both more complex and more profound. Stem cell sources are multiplying almost daily: cord blood, bone marrow, spare embryos, cloned embryos, hybrid embryos, near-embryos, dead embryos. Experts disagree about the usefulness of the various cell types. Citizens disagree about whether we should destroy human embryos for their stem cells—and if so, which embryos, with whose money, under what regulatory guidelines. Research advocates attack President Bush for “banning stem cell research,” while pro-life advocates lament a Republican administration and Congress that have banned nothing—not embryo destruction, not human cloning, not fetal farming, not genetic engineering. Taken together, everyone seems angry or depressed—including the sick patients who wait for cures that do not come, the social conservatives who believe we live in a “culture of death,” and the techno-utopians who believe man’s final conquest of nature is imminent if only the religious barbarians can be driven from power. This is our sad state of stem cell affairs.
But if we are to make wise policy the stem cell/cloning arena, we need to step back, sort out the various scientific alternatives and moral issues, and search for a way forward that all citizens can embrace. To this end, we offer a detailed analysis of the stem cell/cloning question—where is the science, what are the political alternatives, and what moral obligations should guide us?
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1. Adult Stem Cells: Long before the controversy emerged over human embryonic stem cells, scientists and doctors began using first-generation stem cells from adult bone marrow. Today, we can derive stem cells from a range of adult and newborn tissues: liver cells, kidney cells, brain cells, fat cells, and umbilical cord blood. Last May, the House of Representatives passed a bill to create a cord blood stem cell bank, legislation that is likely to become law with virtually unanimous support. Already, non-embryonic stem cells are being used to treat a variety of diseases—most notably certain cancers of the blood. And recent experimental trials, while still very preliminary, suggest that adult stem cells may one day help us treat a host of terrible pathologies. This is all good news.
Yet for now, the utility of adult stem cells also remains limited. Adult stem cells are easier to control than embryonic stem cells and thus less likely to form tumors. But they are also less equipped to produce every cell type of the body and less able to reproduce themselves indefinitely, which makes them less appealing to scientists interested in basic research. The holy grail of regenerative medicine—whatever one’s ethical beliefs about destroying embryos—is to “reprogram” regular cells from one’s own body so that individuals can be the source of their own rejection-proof therapies.
But adult stem cells also raise some interesting ethical dilemmas alongside their great therapeutic promise. In July 2005, for example, scientists announced that they had engineered adult mouse stem cells into usable mouse eggs, a technique that might one day allow for the creation of human eggs from ordinary human cells. Perhaps this is worth celebrating for young women who cannot produce eggs on their own, as a first step toward novel fertility treatments. But we can only wonder about the ethical propriety of producing the first human child with this technique, knowing that the hoped-for newborn would be a reproductive experiment, one that may end initially in numerous fetal failures. And if post-menopausal women begin having children by producing eggs from other parts of their body, we will only aid the revolt against the lifecycle that now defines modern culture.
In addition, the possibility of reprogramming adult stem cells back to a “pluripotent” (or embryonic-like) state raises the biological prospect of going back too far. That is to say, we risk turning developed cells into developing embryos, and thus risk engaging in the very activities of embryo destruction and human cloning that we seek to avoid. These moral perils are surely not a reason to oppose adult stem cell research, which deserves vigorous and expanded public support. But we need to proceed carefully, recognizing that we are gaining new powers over human origins even when we do not use human embryos, and recognizing the danger of blurring the line between cellular parts and embryonic wholes.
2. The Bush Lines: Far more controversial—and for good reason—are stem cells derived from destroyed human embryos. Since 1995, Congress has annually reauthorized a law—called the “Dickey Amendment”—prohibiting federal funding for research “in which” embryos are destroyed while leaving embryo destruction in the private sector entirely unregulated. Before leaving office, President Clinton sought to get around the existing law without actually changing it, by funding research on embryonic stem cells so long as the actual embryo destruction was paid for with private dollars. When he came into office, President Bush halted implementation of the new Clinton policy, plunging the nation into its first great stem cell debate, the defining issue in American politics before September 11.
On August 9, 2001, President Bush announced that any embryonic stem cell lines already in existence, where the embryos in question had already been destroyed, would be eligible for federal funding. There are 78 eligible “derivations,” but only 22 available “Bush lines” of real scientific value, with the expectation of a few more to come in the years ahead, once scientists finish the work of classifying them biologically and lawyers finish the work of negotiating the intellectual transfer agreements. Of course, there is nothing intrinsically sacred about August 9, 2001. But by fixing the date of eligibility, the Bush policy made clear that those who continued to destroy human embryos would not be rewarded with federal funds. The policy aimed to advance embryonic stem cell research without creating a public incentive for ongoing embryo destruction. It was a principled compromise all sides could accept—or so the White House optimistically hoped.
Yet for all the energies spent defending it, the Bush policy was always limited in scope and somewhat problematic in effect. It does nothing to stop embryo destruction with private dollars or state funds. And it directly rewards those researchers who destroyed human embryos in the first place, including corporations who now benefit from the patents they own on the eligible stem cell lines. Yes, there are moral grounds for benefiting from past misdeeds. But doing so requires erecting firm boundaries against the continued propagation of those misdeeds, not rewarding the transgressors with public money. Four years later, no such boundaries exist to limit embryo destruction, which proceeds apace in private laboratories (often with state funding) around the country and around the world.
3. The Existing (“Post-Bush”) Lines: Since August 9, 2001, a large number of new embryonic stem cell lines have been produced with private funds. This means, yet again, that the embryos in question have already been destroyed, raising a difficult question: Are these existing stem cell lines ethically different from the Bush lines, and should they be available for ongoing research or federal funding? Sen. Norm Coleman has a bill that proposes to do just that: move the Bush date forward, so that those embryonic stem cell lines produced since August 9, 2001 would also be eligible for NIH dollars.
Taken by itself, the Coleman bill should be opposed: to move the date, while setting no new limits on embryo destruction, sets a precedent that the date is always movable. It tells scientists that they can destroy human embryos today in the hope of getting public funding in the future. But using the post-Bush lines is not necessarily unethical, so long as those who use them decry the process that created them and do not reward the creators. Moreover, a bill that funded research on all existing stem cell lines (say, as of November 11, 2005) while banning the creation of human embryos solely for research might merit pro-life support, even though it rewards those scientists who destroyed the embryos in the first place. A second Bush compromise of this sort might make political sense—if it would stop future embryos from being destroyed. But moving the date without erecting legal boundaries against embryo destruction would be a moral and political error.
4. “Spare” Embryos: Stem cell lines are very different from living human embryos: they are cells, not organisms; they are akin to human organs taken from cadavers, not nascent human lives in process. Most living human embryos exist in freezers—with around 400,000 frozen embryos in the U.S., according to the best available estimate. Most of these frozen embryos (more than 90%, according to the same study) are not available for research. Many parents still want to preserve the possibility of bringing their frozen embryos to term, and many others simply cannot bear the thought of seeing their embryonic offspring extinguished. So they pay, year after year, to keep their embryos frozen, even though they have no intention of ever bringing them to term. A much smaller percentage of parents have donated their frozen embryos to science, and it is these so-called “spare” embryos that the Castle-DeGette bill wants to use in federally funded experiments.
Research advocates defend using “spare” embryos with great moral simplicity: the embryos are “going to die anyway,” so we might as well get some benefit from them. But these embryos are only going to die because their parents made and abandoned them; their doomed condition says more about our moral standing as the neglectful creators of innocent life than it says about the moral standing of the embryos themselves. And the fact that someone is destined to die is not a moral argument for exploiting them: hospice residents and prisoners on death row are going to die; that does not give us moral permission to harvest their organs.
Politically, the best we can hope for when it comes to frozen embryos is public silence—never endorsing the destruction of left-over embryos with public funds, but recognizing the impossibility or imprudence of trying to mandate what is done with them. The real fight should be about why we are making so many “spare” embryos in the first place, and whether the time has come to regulate the way in vitro fertilization is practiced to prevent creating nascent human lives we never intend to nourish.
5. Creation for Research and Destruction: In reality, research advocates do not want to stop with “spare” embryos; they want to create human embryos solely for research. With fertility treatment, every embryo is at least brought into being with the possibility of life, with the possibility of being implanted, with the possibility of being “the one” who makes it to term. With the creation of human embryos solely for research, every embryo is produced as a mere thing, a research tool, a raw material for our use. The instrumentalization of nascent human life is complete.
When Senator Frist announced his support for funding research on the “spares,” he also called for a ban on the creation of human embryos solely for research and destruction. If the majority leader were serious, he could make his support for funding use of the “spares” entirely contingent on enacting such a ban. This would spur a good political fight: Should we create human life simply to use and destroy it? According to a recent poll by the non-partisan Genetics and Public Policy Center, most Americans say no. And for the past few years, President Bush has made this moral line one of his rallying cries. “To build a culture of life,” he remarked in this year’s State of the Union address, “we must also ensure that scientific advances always serve human dignity, not take advantage of some lives for the benefit of others. We should all be able to agree on some clear standards. I will work with Congress to ensure that human embryos are not created for experimentation or grown for body parts.” A noble sentiment and wise political strategy. But where is the action?
6. Cloned Embryos: Over time, the public debate over IVF embryos may prove a red herring. What scientists want—or “need”—are embryos that they can control genetically. And the best way to exert such control is by creating cloned human embryos, each one with the DNA of a deliberately chosen research subject, using a technique called “somatic cell nuclear transfer.” This genetic control is crucial for two reasons: It allows researchers to produce stem cells from patients with specific diseases, which they can study using stem cell models; and it allows researchers to produce potentially rejection-free stem cells, identical to the patient who might one day receive therapeutic transplants. Stem cells from “spare” embryos will always lack these biological characteristics. Funding the “spares” is really a first step toward funding human cloning for research.
The recent scandal in South Korea revealed the corruption at the heart of the cloning project—the brutal willingness to exploit women for their eggs, the desire to create and destroy mass numbers of embryos treated solely as raw materials, and the moral un-seriousness about cloning itself, and what it would mean to take the first giant technological stop toward the age of cloned babies. For in the deepest sense, human cloning is the corruption of parenthood: it treats the child as an object of manufacture; it robs the young of an open future; it confounds the relationship between the generations; and it imperils one’s offspring in the very act of seeking to give life.
Twice, the House has passed legislation that would ban all human cloning. But for now, the necessary votes do not exist in the Senate. This political stalemate over human cloning has prompted the search for a technical solution to our moral and political divide—one that gives us embryonic stem cells without destroying human embryos, eternal life without original sin. More specifically, the idea is to enter the post-cloning age before the age of cloning really begins, with four new stem cell technologies now competing for prominence.
7. Cadaver Embryos: Many frozen embryos are not really still alive, and many others do not survive the thawing process. One idea, proposed by Donald Landry and Howard Zucker of Columbia Medical School, is that we might harvest embryonic stem cells from these already dead embryos—just as we take organs from already dead individuals. In other words: we should not kill embryos in order to use them; we should not act as the agents of their destruction; but we should exploit those embryos that die on their own.
The idea is clever but problematic. Unlike removing organs from cadavers, the individuals involved in such research are not committed to trying to keep the embryos alive. They wait eagerly for the donor’s death; they don’t try to save the donor’s life. More specifically, using only “cadaver” embryos depends on the scrupulosity of research scientists—who care little about living embryos—to distinguish between thawed embryos that are still living but never implanted and thawed embryos that are already dead at the moment of thawing. Otherwise, this technique is simply a way of deliberately letting embryos die so that we can use them once dead. And from a scientific perspective, stem cells from dead embryos would not allow scientists to control the stem cell genomes, as they can with research cloning. For this reason alone, this solution to our stem cell woes is probably no solution at all.
8. Blastomere Biopsy: Another proposed technique for getting embryonic stem cells without destroying embryos—as described this October in Nature—is to remove a single cell from a living embryo without harming the embryo. If done correctly, this technique is surely preferable to embryo destruction. But it also presents two insurmountable ethical problems. First, the technique of embryo biopsy is relatively new, and we have little definitive research about the long-term effects of the procedure on the development of the embryos born after biopsy. If the biopsied embryos are just discarded, then this technique hardly solves the moral problem of embryo destruction. But if they are implanted to initiate a pregnancy, then we have a new moral problem: endangering a developing child for reasons that do not directly benefit the child.
Second, embryo biopsy is done primarily to engage in “pre-implantation genetic diagnosis,” a way of testing embryos to decide which are healthy and which are sick, which are wanted for birth and which are “unfit to live.” This is, in order words, the in vitro equivalent of amniocentesis, a procedure that leads many parents to abort disabled fetuses. Morally speaking, it makes little sense to build stem cell research on the foundation of a practice used mostly for eugenics, even if doing so means that research scientists will not destroy embryos solely for research. This alternative, in the end, is no real alternative at all.
9. Altered Nuclear Transfer: A third proposed alternative—also described this October in Nature—is “altered nuclear transfer” (ANT). As described above, nuclear transfer is the technique used to engage in human cloning: It involves taking a cell from an adult or infant, removing the cell’s nucleus, transferring that nucleus into a human egg whose own nucleus has been removed, and manipulating the biological result to produce a living, dividing, and potentially implantable cloned embryo. Altered nuclear transfer would modify the genetic make-up of the nucleus before transferring it, so that it lacks the information necessary to produce a cloned embryo. Instead, it would produce a collection of cells that have crucial embryonic qualities without ever becoming a real human embryo.
One cannot help but admire this proposal and the genius behind it: William Hurlbut, a Stanford professor and member of the President’s Council on Bioethics. The idea is morally serious, scientifically creative, and politically engaged. But ANT also raises serious ethical questions, which is why many opponents of embryo research are still uncertain about its merits. First, we need to be sure that we are not simply producing a “disabled human embryo,” pre-programmed to fail in early development. And even if we can settle this question biologically—knowing for sure that there is no embryo present—we need to examine what creating a simulacrum of nascent human life does to our moral sensibilities.
With ANT, human dignity seems to turn on whether a single gene is turned on or off, leaving us to rely entirely on scientific expertise to tell the difference between nascent human beings and sub-human things. To the expert in systems biology, this distinction is clear. To the citizen, it is not. And even as we try to avoid the guilty deed of embryo destruction, there is also something perverse in this novel act of near-embryo creation: We begin with an understanding of what makes a new life flourish, then we delete one crucial ingredient to produce a near-life that we can use. The biological line between responsibility and depravity is so thin that perhaps only angels dare tread.
Like research cloning, ANT also requires using a significant number of human eggs, either donated by women or produced artificially. Morally speaking, it seems unjustified to ask fertile women to endure the violation necessary for egg donation solely to aid a speculative project of research. And it seems unlikely that enough infertile women will produce excess eggs during fertility treatment to meet the research demand. This creates the temptation to produce eggs artificially, and already some scientists have done so in animal experiments, by turning embryonic stem cells into usable eggs. But this path leads to potentially dark places, by giving us the power to produce human children whose mother, father, or both are dead embryos. It would allow us—and tempt us—to produce orphans by design, by using artificial eggs for reproduction, not only research.
It would be a tragic irony if in the effort to avoid destroying human embryos we helped turn human procreation into a Huxleyian form of manufacture. With proper limits, this fate can perhaps be avoided, and ANT probably merits the grudging support of those seeking to stop embryo destruction indirectly by redirecting scientific energies in alternative directions. If it works, this research might truly help the sick and advance our understanding of developmental biology. But ANT’s dangers are also not small, and the technique is hardly innocent.
10. Cell Fusion: This brings us to the final alternative—the one with which we began—called “cell fusion.” This technique, as described above, involves fusing existing embryonic stem cells—like one of the Bush lines—with cells taken from an adult or infant. The product of this fusion is an entirely new embryonic stem cell line, one with all the benefits of research cloning or altered nuclear transfer. We get stem cells with the DNA of the original cell donor, stem cells with genomes that we can control, stem cells that allow us to build disease models or develop rejection-proof transplants—all without using eggs, destroying embryos, or manufacturing near-embryos.
Of course, we should avoid promising technological miracles based on preliminary evidence, as many stem cell advocates are prone to do. Skilled scientists are working intensely on this technique—including Kevin Eggan at Harvard, Yuri Verlinsky of the Reproductive Genetics Institute, and Alan Trounson of the Monash Institute in Australia. But they have a long way to go before we can know just how fruitful this method will be.
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Stepping back, we should hardly be surprised that the stem cell debate has assumed such a prominent place in our public life. For it brings together—and brings into tension—some fundamental parts of the American character: our love of progress, our commitment to the equality of every human being, and our concern with the fate of every individual. This concern for the individual is what drives public support for embryo research, seeing all death and suffering as tragedies to be opposed. But it is also the ground for opposing embryo research, seeing every individual, even the smallest and most vulnerable, as lives worthy of protection.
After eight years of Republican-dominance in politics, it would be a shame if the Bush era ended with no limits on embryo destruction, no limits on human cloning, no limits on fetal farming, no limits on anything. Novel techniques—like cell fusion—may redirect our scientific energies in more responsible directions, and without them our embrace of embryo destruction or worse might come even faster. But technique alone cannot replace the duty of those in public life to address moral issues with moral arguments, or the responsibility of those in power to go on political offense—especially when something as fundamental as the moral foundations of modern medicine lie in the balance. So far, on stem cell research, the Bush administration has failed. Thankfully, it has three years to do better.