Dolly's Creator Moves Away from Cloning and Embryonic Stem Cells

Sitting by the window of a posh coastal hotel in Half Moon Bay, Calif., wearing a baby-blue sweater and khakis, Ian Wilmut doesn't project the image of a scientist who pulled off one of the most dramatic experiments in modern biology. When he and his collaborators unveiled Dolly the cloned sheep in 1997, they ignited the embryonic stem cell research field, struck awe in the public and set off a panic about the imminent cloning of humans. "Dolly was a big surprise to everyone," recalls stem cell biologist Thomas Zwaka of the Center for Cell and Gene Therapy at the Baylor College of Medicine. Cloned frogs had refused to grow past the tadpole stage, and a seeming success in mice had proved to be a fake. According to scientific consensus back then, cloning adult mammals by the method Wilmut used was biologically impossible.

As Dolly matured, the cloning technology that created her-called somatic cell nuclear transfer (SCNT)-grew into a rich research enterprise. Scientists hoped to eventually be able to take a patient's cell, place its nucleus into an unfertilized human...