in 1997 photographs of a sheep call

in 1997 photographs of a sheep called Dolly appeared on the front page of newspapers around the world. She looked quite ordinary, but Dolly was different from other sheep. She was an identical copy from another adult sheep. In other worlds, she was a clone. Before Dolly, scientists had only been able to clone large animals using cells taken from embryos. They had tried to do it using cells from adult animals, bt it hadn't worked-until now. That's why Dolly was so special.

Lost of animals have been cloned since then, including cows, monkeys and cats. Cloning technology is also being used to try to keep some animals from becoming extinct. But be still don't understand the technology very well. The scientists who created Dolly tried 276 times before they were successful. Many cloned animals die soon after they are born, and those that survive often become ill later.

Since Dolly's arrival, some people have suggested that humans might also be cloned one day. The idea is very controversial. A lot of people think it would be wrong, including some of the scientists who created Dolly. But other think it would be okay in some situations, such as helping scientists to find a cure for a disease. whether it's right or wrong, cloning humans will be possible one day. It's up to us to decide what happens next.