She may be the most famous animal ever to walk on Earth. She was a sheep named Dolly—and she was an exact copy of another living sheep.
Dolly was born in Scotland in 1996. The announcement of her birth made headlines in newspapers around the world. The lab that produced her received 3,000 phone calls the next week. Most of the callers were shocked that a sheep had been cloned, and they had one important question: Were humans next?
To some people, the idea of cloning humans was exciting. The science of cloning could lead to cures for diseases. And what about parents whose children had died? Maybe they should have the opportunity to replace their beloved kids with clones.
But other people found the idea frightening. What if movie studios started cloning the most attractive actors? What if wealthy parents bought cells from geniuses to produce smart kids?
The future suddenly felt dangerous. Dozens of countries made it illegal to clone humans.
In the 23 years since Dolly’s birth, scientists have cloned mice, cows, pigs, goats, rabbits, cats, and dogs. However, no one has figured out how to clone a human being. It may still happen in the future—but for now, the only clones walk on four legs.