What image does the word cloning conjure up in your mind? Jurassic Park with its labs full of cloned dinosaur embryos? News headlines about cloned kittens and cloned monkeys? Star Wars and Attack of the Clones? Or even – cloned human beings? Cloning has had a lot of sensational media coverage in many ways – so what are the facts behind the hype?

People have been cloning plants for centuries by taking cuttings, the method used to produce these spectacular bromeliads.

A clone is a group of cells or organisms which are genetically identical and have all been produced from the same original cell. If you know any identical twins, you know some clones. Identical twins are natural clones of each other. All of the bacteria, plants and animals that have been produced as a result of asexual reproduction are also clones – in fact people have been cloning plants for centuries by taking cuttings. The big change over the last 50 years is that we have developed the ability to produce clones artificially. Not only that, but we can produce animal as well as plant clones.

Here we shall look exclusively at animal cloning, because this is the area in which there is the most biomedical potential – and also where much of the most exciting and controversial work is taking place. There are three main types of cloning , two of which aim to produce live cloned offspring and one which simply aims to produce stem cells and then human organs.