...of arthritis in Dolly the sheep has renewed concerns that the world's first cloned mammal may be aging prematurely. Ian Wilmut, the professor who cloned Dolly in 1996, revealed Friday that the sheep began to limp several weeks ago and was found...

...a new study that raises doubts about cloning animals for human transplantation and about cloning humans themselves. Ian Wilmut, the pioneer researcher who cloned the sheep Dolly, says the report raises the question of whether any clones are entirely...

...Discoveries of 2007, and the journal Science rated it the No. 1 breakthrough of 2008. The iPS discovery even prompted Dr. Ian Wilmut, who cloned Dolly the sheep, to abandon his license to attempt human cloning, saying that the researchers may have...