Saving lives has always been an important mission of science. Now science, and indeed all society, is facing a new dilemma:whether or not to try and save more lives through human cloning. The first cloning experiments in the 1950s involved frogs and toads. It was not until 1997 that scientists successfully cloned the first mammal, the now world-famous sheep known as Dolly. Cloning techniques have continued to improve since then, and today there are cloned mice, salmon, and cattle.