“Scientists clone adult sheep,” read the headline splashed across the front of a British newspaper in the winter of 1997. Soon, the rest of the world would meet Dolly, the product of a team of Scottish scientists who took a mammary cell from an adult sheep, fused it to another sheep’s unfertilized egg and created an identical twin.

A rush of media attention gave way, almost instantaneously, to speculation and anxiety about what this new discovery meant for man’s ability to manipulate biology — a controversy compounded by a brewing debate over the ethics of embryonic stem cell work.

Dolly’s story explores the friction between science and politics, and what happens when a breakthrough is so tangible and profound that it provokes both our highest hopes and greatest fears.