In what scientists say is a stunning leap forward, a team of South Korean researchers has developed a highly efficient recipe for producing human embryos by cloning and then extracting their stem cells.
Writing today in the journal Science, they report that they used their method to produce 11 human stem cells lines that are genetic matches of 11 patients aged 2 to 56.
Previously, the same group, led by Dr. Woo Suk Hwang and Dr. Shin Yong Moon of Seoul National University, produced a single stem cell line from a cloned embryo, but the process was so onerous that scientists said it was not worth trying to repeat it, and some doubted the South Koreans’ report was even correct.
Now things have changed.
“It is a tremendous advance,” said Dr. Leonard Zon, a stem cell researcher at Harvard Medical School and president of the International Society for Stem Cell Research, who was not involved in the research.
The method, called therapeutic cloning…