Scientists at a small biotechnology company say they have used cloning to create human embryos from the skin cells of two men.
The work represents a step toward the promise of creating personalized embryonic stem cells that could be used for medical treatments. Although the embryos grew only to a very early stage, the work could also theoretically be seen as a step toward creating babies that are genetic copies of other people.
Scientists at the company, Stemagen, which is based in San Diego, said Thursday that they were the first to use human adult cells to create cloned embryos that advanced to the stage known as a blastocyst, from which embryonic stem cells typically are extracted.
However, the researchers did not derive embryonic stem cells. That left some experts skeptical.