In 1996, a team of scientists from Scotland lead by Ian Wilmut produced Dolly the sheep, the world's first mammal clone. The method used was nuclear-transfer technology. The sheep attracted 2000 telephone calls, nearly 100 reporters, 16 film crews and over 50 photographers.

Dolly is a clone of the first sheep, whose single cell was taken. The unusual thing was that Dolly's udder cell was fully grown. The research team had to make the cell young. Part of the procedure was to starve it. This process made the egg cell believe that it was meeting a young cell, so the growth process started naturally. No scientist know why the plan worked, and in 1998, Dolly gave birth to three lambs, which showed that she was healthy and that clones could reproduce.

Unfortunately, she was given a lethal injection after there were signs of progressive lung disease on Februrary 14, 2003.