Destructive impulse

Science | Why aren't cloning advocates happier about recent stem-cell breakthroughs? | Lynde Langdon

Professor Ian Wilmut of the University of Edinburgh envisions a world where sick people could draw new life from younger, healthier clones of themselves. Mr. Wilmut became famous for cloning Dolly the Sheep and is now one of the most prominent embryonic stem-cell and human-cloning researchers.

Scientists at Harvard University announced last week that they had taken a small but hopeful step toward the type of medical treatment Mr. Wilmut envisions, but without the need to clone human beings. Mr. Wilmut acted unimpressed. He quickly noted that the Harvard research needed a lot of work before it would be medically useful.

"In the meantime, let us not waste time," Mr. Wilmut told reporters in London. "There are methods of deriving embryonic stem cells from cloned embryos that could be used to study and, in time, to treat human disease. Let's get on with this, for the sake of thousands of patients."