Cloning means making a living thing from another living thing such as a plant or animal. The process uses the genes of the first so they both have identical DNA.

In the last few decades scientists have been trying to clone animals.

They transplant DNA (the gene pattern which makes living things unique) from the cell of one animal into the cell of another which has had its DNA taken out.

Now scientists in America have announced that they have created a clone of a human embryo.  

In 1997 Dolly the sheep became the first ever cloned mammal.

Scientists in Scotland used a new type of technique. When Dolly was born months later, it had taken 276 tries to get it right.

Since Dolly, cows, pigs, monkeys, rodents, cats, mules, horses and dogs have been cloned.

Animals or plants with special qualities could be mass produced to help in the manufacture of important drugs.

You could replace pets which have died or even repopulate endangered or extinct species.

In 2001 the first clone of an endangered animal was born; a baby bull gaur (a wild ox) called Noah.

Although Noah died of an unrelated infection, the experiment showed it's possible to save endangered species through cloning.

Can people be cloned?  

There's a lot of controversy over this one.

An announcement by an American company that it has created a human embryo clone is being viewed as both an incredible scientific achievement and a dangerous step.

In 2005, British scientists announced they had successfully cloned the country's first human embryo. The only thing they plan to do with this research is to use cells from the embryos to help treat disease in the future.

It was made illegal to clone embryos to make babies in 2001.  Opponents of cloning say cloning humans is very wrong because it goes against nature.

Why would we want to clone ourselves?  

It doesn't have to be a whole human being which is cloned. Scientists could copy our cells and fix genes that cause diseases. Or new organs like skin or hearts could be grown to help people who are ill.  People who can't have babies might also be helped.  

What's the problem with cloning?  

About 98% of cloning efforts fail. Usually a cloned embryo dies before birth but sometimes afterwards too. Most of the survivors have potentially fatal heart or lung problems or diseases like diabetes.