Efforts to create embryonic stem cells using cloning techniques should be put on hold for the time being, according to the Center for Genetics and Society, a public interest organization.
"The successes in cell reprogramming suggest that scientists can achieve the goals of cloning-based stem cell research by other means," said Marcy Darnovsky, associate executive director at the Center.
"Given its risks and lack of progress, it's time to put research cloning on the back burner. If the new techniques don't deliver on their promise, then the cloning issue can be revisited."
For years, some stem cell scientists have sought to use cloning to derive disease-specific and patient-specific stem cell lines. Yesterday, two research teams announced they had isolated such cells without cloning.
"Cloning-based stem cell research lays the technical groundwork for the reproductive cloning of humans, and it requires enormous numbers of fresh eggs, whose extraction poses health risks to women," said Jesse Reynolds, policy analyst at the Center. "And after years of work, no researcher has created a clonal human embryo viable enough to yield stem cells. At this point the risks clearly outweigh the possible benefits."
Most embryonic stem cell research uses embryos left over from IVF procedures, but cloning requires unfertilized eggs, which are difficult to obtain and preserve. Just two weeks ago, the first stem cell lines were derived from a primate - a rhesus monkey - but this required hundreds of eggs.
"Researchers who continue to insist on cloning are painting themselves into a corner for no good reason," Darnovsky added. "At this point, those who say we should pursue all possible avenues of research are dismissing the risks to women who would provide the eggs they would need for their experiments. They're also downplaying the potential for reproductive cloning, especially given the absence of a U.S. law against it."
In response to the successes of cell reprogramming, leading cloning researcher Ian Wilmut announced that he is abandoning that avenue of work in favor of the new methods.
"The new techniques give us new options," noted Reynolds. "Now that we can take embryo politics out of the stem cell issue, we can begin to address some of the pressing regulatory challenges raised by emerging biotechnologies. We need national and international bans on reproductive cloning, and comprehensive federal policies to regulate other powerful new genetic technologies."
The Center for Genetics and Society is a policy research and advocacy organization. It supports embryonic stem cell research under conditions of responsible societal oversight and regulation.