Scientists at a California company reported yesterday that they had created the first mature cloned human embryos from single skin cells taken from adults, a significant advance toward the goal of growing personalized stem cells for patients suffering from various diseases. Creation of the embryos -- grown from cells taken from the company's chief executive and one of its investors -- also offered sobering evidence that few, if any, technical barriers may remain to the creation of cloned babies. The study leader, who is also the medical director of a fertility clinic ... emphasized that he has no interest in cloning people. It's unethical and it's illegal, and we hope no one else does it either," said Samuel H. Wood, chief executive of Stemagen in La Jolla, whose skin cells were cloned and who led the study. The closely held company hopes to make embryos that are clones, or genetic twins, of patients, then harvest stem cells from those embryos and grow them into replacement tissues. Opponents of research on human embryos lashed out at the approach. "This study seems to confirm that human cloning ... is technically possible," said Richard Doerflinger of the U.S. Conference of Catholic Bishops. "It does not answer the ethical or social questions about the mass-production of developing human lives in order to destroy them. It only tells us that these questions are more urgent than ever." Other critics noted that scientists in Japan and Wisconsin recently discovered a way to "reprogram" stem cells directly from skin cells, without having to make embryos as a middle step. "In light of the recent cell reprogramming developments, cloning-based stem cell research is less justified than ever," said Marcy Darnovsky of the Center for Genetics and Society.

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