So far, stem cells haven’t lived up to their promise of regenerating failed organs and correcting genetic defects. Although stem cells can become any type of cell the body needs, isolating them and directing their metamorphosis can be risky and unpredictable. Besides, there are relatively few sources — human embryos among them — from which to collect them. Special techniques that insert genes directly into cells make it possible to turn specialized adult cells — bone or skin cells, for example — back into stem cells. But that process is error-prone and can even incite cancer. Now researchers at the Scripps Research Institute may have conquered several of those barriers. Instead of shooting genes into cells, researchers tested mouse cells against millions of antibodies, which can spark the needed genetic changes more naturally. Based on the antibodies the cells took up and the results, the scientists isolated a few antibodies that can turn adult cells into stem cells without the attendant problems. Next, the Scripps group will test the antibodies on human cells.