Stem cells, a type of universal cell in early embryos, can in theory grow into any of the body's tissues and organs. But embryonic stem cells are drawn from human embryos after they have grown for about five days in the lab, and obtaining those cells requires that the embryos be destroyed. The moral objection has been that that is destroying human life.
So while most stem cell scientists focus on obtaining stem cells from early embryos, Dr. Daley and Dr. Jaenisch have begun asking if they can get stem cells another way, perhaps by creating aberrant cell clusters that contain stem cells but could never survive more than a week or so. The idea is to produce embryonic cells without the embryos and make nearly everyone happy.
Full Article.... http://www.nytimes.com/2005/10/11/health/11stem.html?th&emc=th