Will Dolly Send in the Clones?

Dolly, the lamb cloned from an udder cell of an adult ewe, has sparked an intense debate about the prospect of human cloning. But researchers say it's still unclear how practical cloning of animals, let alone humans, will be. The procedure so far is inefficient; the group that created Dolly made 277 previous attempts. And no one yet knows whether the cloning procedure, which involves transferring nuclei from adult cells into eggs whose own nuclei have been removed, will work with other species.