South Koreans clone cells

WASHINGTON — South Korean researchers are reporting that they have developed a highly efficient recipe for producing human embryos by cloning and then extracting their stem cells.

Writing in the journal Science, the researchers, led by Dr. W.S. Hwang and Dr. S.Y. Moon of Seoul National University, said that they used their method to produce 11 human stem cell lines that were genetic matches of patients who ranged in age from 2 to 56.

The method, called therapeutic cloning, is one of the great hopes of the stem cell field. It produces stem cells, universal cells that are extracted from embryos, killing the embryos in the process, and that, in theory, can be directed to grow into any of the body's cell types.

Because the stem cells come from embryos that are clones of individuals, they would be exact genetic matches. Scientists want to obtain such stem cells from patients with certain disorders and illnesses to study the origin of diseases and to develop replacement cells that would be identical to those a patient has lost in a disease like Parkinson's.

Hwang said he had no intention of using the method to produce babies that were clones. "Our proposal is limited to finding a way to cure disease,"' he said. "That is our proposal and our research goal."

Previously the same group produced a single stem cell line from a cloned embryo, but the process was so onerous that many scientists said it was not worth trying to repeat it, and some doubted the South Koreans' report was even correct.

Things have changed.

The new finding buoyed researchers who had wanted to use such stem cells to study diseases but had thought it would be years, if ever, before it would be practical to obtain them. "It is a tremendous advance," said Dr. Leonard Zon, a stem cell researcher at Harvard Medical School and the president of the International Society for Stem Cell Research, who was not involved in the research.

But the report raised concerns among others, who said it was a step down the slippery slope leading to cloned babies. Richard Doerflinger, director of pro-life activities at the U.S. Conference of Catholic Bishops, said: "Up until now, people were beginning to wonder whether human cloning for any purpose was feasible at all. This development makes it feasible enough to be a clear and present danger."