Controversial step in regenerative medicine reported

Biologists in South Korea reported Thursday the creation of the first stem cell lines engineered to carry the DNA of patients with chronic disease and injury, a development hailed by some as perhaps the most significant technical advance for regenerative medicine since stem cells were isolated from human embryos in 1998.

But the report also raised new controversies, because the scientists used refined cloning methods to create the new stem cell colonies.

"Patient-specific" stem cells are expected to be invaluable as laboratory tools to study the genetic roots of diseases and to develop new treatments that might arrest the process long before symptoms appear. Eventually, scientists hope to use embryonic stem cells to find new ways to diagnose and treat such mysterious ailments as autism and schizophrenia.

The research was reported Thursday in the online edition of the journal Science.

"It's spectacular," George Daley, a stem cell biologist at Harvard University, said of the research. "It's moved the field so far forward and so much more quickly than anticipated."

The South Korean scientists also...