Despite over a decade of hype, cloning-based stem cell research has offered little in the way of scientific progress. It has been more symbol than substance; more moving target than realistic goal. However, by complicating both politics and policy, is has been a monkey wrench in the gears for progressive advocates of responsible biotechnologies.
Although there had been previous technological and policy developments in reproductive cloning, the 1996 birth of Dolly the Sheep - the first cloned mammal - catalyzed widespread concern and numerous laws about human reproductive cloning throughout the world. It quickly became clear that, outside of a handful of extreme techno-enthusiasts, reproductive human cloning had few defenders. Prohibitions in every nation, and even internationally, seemed to be just around the corner.
But two years after Dolly's birth, scientists led by James Thomson at the University of Wisconsin isolated human embryonic stem cells. These cells' power to differentiate into any tissue type - a characteristic called pluripotency - represented the foundation of a potential new type of medicine, in which cellular therapies could be used to repair the degenerative tissue at the core of many diseases. Furthermore, because they could be cultured as cell lines, another more feasible use of embryonic stem cells would be as in vitro standards in which human biology-both normal and abnormal - could be observed and tested at cellular level.
However, many stem cell scientists focused on the limits of this source of stem cells for therapeutic purposes. Because the cell lines were derived from embryos created but not used for fertility treatment, their genomes were essentially random. Any potential cellular therapies posed the risk of immune rejection by the patient. Furthermore, researchers wanted stem cell lines that harbored all the genetic contributors to a particular disease to serve as a "disease in a petri dish." Thus, some scientists and advocates called for the derivation of stem cell lines from human embryos created by the same cloning method used to produce Dolly.
Proposals for such cloning-based stem cell research, often called somatic cell nuclear transfer (SCNT), complicated the politics and policy of both embryonic stem cell research and reproductive cloning. Because the great majority of opposition to embryonic stem cell research was based on the moral status of embryos, it was a divisive issue which mirrored the abortion debate. In contrast, reproductive cloning was opposed nearly unanimously. Proposals to use cloning technology in stem cell research, though, linked these two issues, conflating them in the minds of some observers and policy makers.
Beliefs that assign full moral status to human embryos preclude support for any embryonic stem cell research, whether the cell lines are derived from excess IVF embryos or from (hypothetical) cloned embryos. But there are reasons unrelated to embryo destruction to be concerned about SCNT, and many who support stem cell research using IVF embryos have raised significant concerns about SCNT. Most obviously, SCNT could lay the groundwork for reproductive cloning. Technically, it would perfect cloning methods. Logistically, it would entail creating numerous clonal embryos, requiring only implantation into a woman's womb for potential reproductive application.
Moreover, SCNT requires human eggs, and its experimental development or application to create stem cell lines would call for large numbers of them, perhaps hundreds of thousands. Their only source is women, and egg extraction is an unpleasant, invasive procedure that poses nontrivial health risks. From whom would these eggs come? Should researchers offer cash incentives? Would it be appropriate to do so, knowing that the women who would put their health at risk for a speculative line of research would likely be disproportionately poor and simultaneously less likely to have access to any medical advances?
The political landscape shaped by these questions was a surprising hodgepodge. Of course, opponents of embryo-destructive research stood against any type of cloning, while most scientists and research advocates backed SCNT. But many progressives oriented toward social justice were concerned about the potential exploitation of poor women. Women's groups themselves were divided: Most backed embryonic stem cell research, but some balked at SCNT due to its need for widespread egg extraction. Although public opinion polls on this topic are susceptible to strong wording effects, the most clearly phrased ones indicated that a slim majority of the American public was opposed to cloning for stem cell research.
In the face of these uncertainties about research cloning, federal progress toward prohibiting reproductive cloning slowed. Policy makers faced the question of whether to ban both types of cloning, or just reproductive cloning. A divided answer led to stalemates not just in the US Congress, but also at the United Nations. Today, the United States remains one of the few industrialized countries with no national law prohibiting reproductive cloning.
Despite the fact that cloning-based stem cell research appears unlikely ever to be a feasible endeavor, its supporters indulged in a great deal of hype in the early part of this decade. Although most scientists were measured in their assessments, SCNT enthusiasts portrayed it as an essential and inevitable component of cellular therapies. For example, at the 2004 Democratic National Convention, Ron Reagan, Jr. asserted that we would each soon have our own "personal biological repair kit standing by at the hospital."
Such unrealistic proclamations helped fuel strange policy proposals and political debates. For example, in 2006 Missouri devoted a lot of political attention and campaign cash to a constitutional amendment that would have done little besides protect SCNT from potential state laws - despite the fact that no ban on SCNT was likely to ever be enacted in Missouri, and that no researchers there were conducting cloning-based stem cell research. Nevertheless, a single wealthy couple poured over $30 million into the ballot battle, in a state with slightly more than two million voters. That made it not only the state's most expensive contest, but more expensive than all the state legislative races combined. Although the proposal passed, SCNT research is still not taking place in Missouri.
More relevant policy debates have focused on whether to permit payments (beyond reimbursement for expenses) for providing eggs for cloning-based stem cell research. Many jurisdictions both in the U.S. and abroad prohibit such payments. For example, California's Proposition 71, which passed in 2004 to make that state the world's largest funder of embryonic stem cell research, doesn't permit financial inducements. The following year, this was reinforced nationally with the National Academies' recommended guidelines for human embryonic stem cell research. A number of countries (including South Korea, China, Japan, Israel, Australia, and the United Kingdom) also ruled against the practice.
More recently, efforts have been made to chip away at this near-consensus. The United Kingdom now permits fertility clinics to give significant discounts if the woman agrees that some of her eggs can be diverted to research. And New York State, which like California has its own funding program, just became the first jurisdiction to explicitly endorse payments for eggs.
In 2007, the political and scientific landscapes for stem cell research were dramatically rearranged when two research teams - one again led by Thomson, the other by Japan's Shinya Yamanaka-reprogrammed normal body cells into fully powerful stem cells. These "induced pluripotent stem cells," or iPS cells, meant that stem cell lines could be produced without destroying embryos. But the development did more. It achieved the goals of SCNT - fully pluripotent stem cells with a known genome, and the ability to produce disease-specific and patient-specific cell lines - without cloning and its need for eggs. Soon thereafter, other teams derived iPS cell lines from people with a variety of diseases, creating the cellular disease models that researchers long had wanted. As a result, scientists began to shift their efforts away from SCNT. One of the early and best known to take this step was Ian Wilmut, leader of the research team who had created Dolly.
Since then, both research on and advocacy for cloning-based stem cell research has dramatically decreased. This is not to say there has been no technical progress. In 2008, the first human clonal embryo was created, though stem cells were not derived from it, as was the first primate clonal stem cell line. But promises of "personal biological repair kits" with concomitant demands for cloning and eggs have largely subsided.
In the meantime, President Obama and the National Institutes of Health have loosened the previous administration's unwarranted restrictions on federal funding of stem cell research using excess IVF embryos. The new rules do not permit federal funding for SCNT. In addition to drawing an appropriate line in his funding policy, the President made another important point in his March 9 remarks on stem cells and cloning, when he said that reproductive cloning is "dangerous, profoundly wrong, and has no place in our society, or any society."
These welcome developments direct our attention to the unfortunate fact that in the United States, human reproductive cloning remains legal at the federal level and in most states. Beyond that, those of us working to ensure that human biotechnologies are developed, used and regulated according to principles of social justice and human rights must confront proposals to tinker with, and perhaps even redesign, the human genome.
Jesse Reynolds is a policy analyst at the Center for Genetics and Society. He holds a MS in Environmental Science, Policy, and Management from University of California, Berkeley.
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