The Niche

Former head of Bush council on bioethics says make embryos for research–in five years

The former head of President Bush’s council on bioethics, now says there shouldn’t be a ban against cloning human embryos for research. Instead, there should be a five-year moratorium against the process. Writing in the Weekly Standard, Leon Kass decries the fact that the US Congress did not pass a law blocking all forms of human cloning, and then says that this stricter form of the law is unnecessary now that researchers can turn to alternate ways of reprogramming.

Instead, he argues for a law that would ban “all attempts to conceive a child save by the union of egg and sperm (both taken from adults).” That’s because the new reprogramming techniques mean that a skin cell could generate egg and sperm cells, whether taken from a man or a woman (or a boy or a girl, for that matter).

Embryos created for the purposes of research would not be outlawed, but instead banned for four or five years as researchers are given more funds to perfect the reprogramming techniques. He does not rebut, because he does not raise, the argument that stopping work the creation of embryos for research through somatic cell nuclear transfer will delay efforts to prefect reprogramming techniques.

Kass writes “Cloning for the purpose of biomedical research has lost its chief scientific raison d’être” (i.e. making a pluripotent cell line genetically matched to a patient.) That’s because it will probably be much easier to reprogram whole cells from adult biopsies than it will be to pull out an adult cell’s nucleus, plop it into a donated egg, grow that “reconstituted embryo” to a blastocyst and make embryonic stem cells.

Kass is probably right, but he fails to mention two caveats.

First, while many scientists are hopeful that so-called induced pluripotent stem cells will really behave like embryonic stem cells, they still aren’t sure. Possibly, a reprogrammed skin cell could be coaxed into a pancreas cell or a heart cell, transplanted, and then “remember” that it started out as a skin cell. Also, no one wants to use the current technique (using viruses to insert genes at random places in the cells’ chromosomes) to make cells that would actually get put into people. Those are serious problems, but most scientists think they can be overcome.

Second, and more important, many scientists think that to understand how reprogramming works with viruses, they have to understand how reprogramming works in an egg. Most people think that requires transferring adult nuclei into eggs or early embryos, and trying to figure out what happens.

Just a little quibble: Kass says that recent success by Stemagen in cloning a human blastocyst depended on the technique that Shoukhrat Mitalipov’s team in Oregon used to clone monkey blastocysts to make embryonic stem cells . Actually, Stemagen did not use this technique but credits its success not with a new technique but with a supply of high quality eggs.


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