South Korea say they are the first to successfully clone a human embryo

S. Korean scientists clone human embryo

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.

But 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 won't 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.

But 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 are discussing the research Thursday at a meeting of the American Association for the Advancement of Science. Details will be published in the journal Science.

It's 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.

Still, "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."

But 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 - but scientific support for therapeutic cloning is high.

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."

"With 100 million patients waiting for breakthroughs in transplant medicine, it would be unethical to stop the research, especially now," added Carl Feldbaum of the Biotechnology Industry Organization. With "an uncertain political climate ... its no coincidence that much of the groundbreaking work in this field is being done overseas."

Internationally, the United Nations recently postponed a decision on what kinds of human cloning to ban. The United States is pushing for a total ban; Britain is leading the call for cloning for medical experiments to be left unhindered.

The Seoul researchers collected 242 eggs from 16 unpaid volunteers. Each woman also donated some cells from her ovary.

Using the same process as is used to clone animals, they removed the gene- containing nucleus of each egg and replaced it with the nucleus from the donor's ovarian cell.

Chemicals jump-started cellular division, resulting in 30 blastocysts, early-stage embryos that contain a mere 100 cells. From those, they harvested just one colony of stem cells - a small success rate.

Those stem cells began forming muscle, bone and other tissues in test tubes and when implanted into mice, the Seoul team reported.

Now, the team is studying how to direct which tissues those cells form, said Woo, who pledged in an e-mail interview to make the new cell line available to other interested scientists.

But Jaenisch lamented that many U.S. scientists couldn't work with the new cell line. Bush administration policy forbids any federally funded research on stem cells from embryos destroyed after Aug. 9, 2001