Wednesday, Nov. 25, 2009


In a controversial breakthrough, a British team used embryonic stem cells to generate what appear to be functioning sperm cells. But the researchers do not plan to implant an embryo created with the sperm into a human carrier. It's uncertain if the sperm would function normally, and in any event, British law forbids such an experiment. But the achievement is an important proof of concept and may allow doctors to generate sperm from the cells of a male cancer patient who is rendered infertile by chemotherapy, permitting him to father children.