Stem Cell Milestone Announced

Scientists have made ordinary human skin cells take on the chameleon-like powers of embryonic stem cells (2), a startling breakthrough that might someday deliver the medical payoffs of embryo cloning without the controversy.

The "direct reprogramming" technique avoids the ethical, political and practical obstacles that have stymied attempts to produce human stem cells by cloning embryos.

Scientists prize embryonic stem cells because they can turn into virtually any kind of cell in the body. The cloning approach -- which has worked so far only in mice and monkeys -- should be able to produce stem cells that genetically match the person who donates body cells for cloning. That means tissue made from the cells should be transplantable into that person without fear of rejection.