It's been 30 years since Dolly the sheep was born—where is cloning technology now?

When Dolly the sheep—the first cloned mammal—was born 30 years ago, she became one of the most famous animals in science history.

Her arrival sparked predictions of a sci-fi future filled with cloned pets, cloned humans and even resurrected extinct animals like the wooly mammoth.

But the reality of cloning has turned out to be much more complicated. ...