WASHINGTON - Researchers in South Korea have become the first to successfully clone a human embryo, and then cull from it master stem cells that many doctors consider key to one day creating customized cures for diabetes, Parkinson's and other diseases.
This is not cloning to make babies, but to create medicine.
It immediately revived controversy over whether to ban all human cloning, as the Bush administration wants, or to allow this therapeutic cloning that might eventually let patients grow their own replacement tissue.
We have to do this research because of its promise for treating disease
said Dr. Moon Shin-yong of Seoul National University, who co-led the new research.
Without cloning, stem cells will not be genetically identical to the patient who needs them, causing a rejection problem and we would like to overcome it Moon told The Associated Press. This kind of science should be conducted in South Korea and in the United States. It is very important to medicine.
Embryonic stem cells are the body's building blocks, cells from which all other tissue types spring. They're present in an embryo only days after conception and are ethically sensitive because culling stem cells destroys the embryo.
Scientists have used therapeutic cloning to partially cure laboratory mice with an immune system disease. And they can cull stem cells from human embryos left over in fertility clinics.
Attempts to clone human embryos, to supply stem cells, have failed until now.
The Seoul scientists say they succeeded largely because of using extremely fresh eggs donated by South Korean volunteers and gentler handling of the genetic material inside them.
Moon and colleague Woo Suk Hwang discussed the research yesterday at a meeting of the American Association for the Advancement of Science. Details will be published in the journal Science.
It is elegant work that provides long-anticipated proof that human therapeutic cloning is possible, said stem-cell researcher Dr. Rudolf Jaenisch of the Whitehead Institute for Biomedical Research in Cambridge, Mass.
It's not of practical use at this point
Jaenisch cautioned.
Years of additional research are required before embryonic stem cell transplants could be considered in people, he stressed.
Critics immediately urged Congress to ban all forms of human cloning. The House last year voted to do that, but the Senate stalled over whether there should be an exception for some research.
The instrumentalization of human life for the benefit of others demeans the value of all human life
said Sen. Sam Brownback, R-Kan., who has sponsored legislation for a complete ban.
There's nothing to stop the next cloned embryo from being used for pregnancy, contended Richard Doerflinger of the U.S. Conference of Catholic Bishops.
The how-to instructions have been posted
he said. If you can bring an embryo to the one-week-old stage
you can implant that embryo in the womb. Once you do
no government can stop you unless they want to coerce abortions.
Stem-cell proponents hailed the research as a crucial first step to one day alleviating diabetes, Parkinson's and other diseases.
It does show what is possible and provides hope to millions
said Daniel Perry of the Coalition for the Advancement of Medical Research.
U.S. scientists almost universally want a ban on reproductive cloning because the high rate of birth defects in cloned animals shows the technique is too dangerous.
The South Korean research is one tiny step closer to some medical use
said Laurie Zoloth, a Northwestern University bioethicist. It is clearly time - now that it is more tangible - to set in place a process where we can have some kinds of experiments supported and some things banned.
