Stem Cell Breakthrough Is Like 'Turning Lead Into Gold'

In an unprecedented feat of biological alchemy, researchers have turned human skin cells into stem cells that hold the same medical promise as controversial embryonic stem cells.

Two teams of researchers -- one led by Kyoto University's Shinya Yamanaka, the other by the University of Wisconsin's Junying Yu -- used a virus to add four new genes to skin cells. Thus transformed, the reprogrammed cells became capable of changing into nearly any cell type in the human body. Embryonic stem cells also have this ability, and may someday be used to cure degenerative diseases, grow new organs and even replace limbs.

"It's a new era for stem cells," said Robert Lanza, chief science officer of Advanced Cell Technologies, a cloning company in California. "It's the holy grail. It's like turning lead into gold."

Scientists have hailed embryonic stem cells as one of the most promising research fields in medicine, saying they could lead to myriad therapies. But currently, many stem cells are derived from embryos, which is a lightning rod issue that crosses political and religious lines...