WHY CLONE?

Research advances over the past decade have told us that, with a little work, we humans can clone just about anything we want, from frogs to monkeys and probably even ourselves!

So, we can clone things, but why would we want to? Let's look at some of the reasons people give to justify cloning.

1. Cloning for medical purposes

Of all the reasons, cloning for medical purposes has the most potential to benefit large numbers of people. How might cloning be used in medicine?

• Cloning animal models of disease
  

  Much of what researchers learn about human disease comes from studying animal models such as mice. Often, animal models are genetically engineered to carry disease-causing mutations in their genes. Creating these transgenic animals is a time-intensive process that requires trial-and-error and several generations of breeding. Cloning technologies might reduce the time needed to make a transgenic animal model, and the result would be a population of genetically identical animals for study.

• Cloning stem cells for research
  

  Stem cells are the body's building blocks, responsible for developing, maintaining and repairing the body throughout life. As a result, they might be used to repair damaged or diseased organs and tissues. Researchers are currently looking toward cloning as a way to create genetically defined human stem cells for research and medical purposes. To see how this is done, see Creating Stem Cells for Research, a component of the Stem Cells in the Spotlight module.

• "Pharming" for drug production

  Farm animals such as cows, sheep and goats are currently being genetically engineered to produce drugs or proteins that are useful in medicine. Just like creating animal models of disease, cloning might be a faster way to produce large herds of genetically engineered animals. Find out more about this research in the feature article Pharming for Farmaceuticals.

2. Reviving Endangered or Extinct Species

Have you seen Jurassic Park? In this feature film, scientists use DNA preserved for tens of millions of years to clone dinosaurs. They find trouble, however, when they realize that the cloned creatures are smarter and fiercer than expected.

Could we really clone dinosaurs?

In theory? Yes. What would you need to do this?

• A well-preserved source of DNA from the extinct dinosaur, and
• A closely related species, currently living, that could serve as a surrogate mother

In reality? Probably not. It's not likely that dinosaur DNA could survive undamaged for such a long time. However, scientists have tried to clone species that became extinct more recently, using DNA from well-preserved tissue samples. For an example, see "Can we really clone endangered or extinct animals?" on the right side of this page.

3. Reproducing a Deceased Pet

No joke! If you really wanted to, and if you had enough money, you could clone your beloved family cat. At least one biotechnology company in the United States offers cat cloning services for the privileged and bereaved, and they are now working to clone dogs. But don't assume that your cloned kitty will be exactly the same as the one you know and love. Why not? See Cloning Myths.

4. Cloning Humans?

To clone or not to clone: that is the question. The prospect of cloning humans is highly controversial and raises a number of ethical, legal and social challenges that need to be considered. To explore some of these, see What are Some Issues in Cloning?

Why would anyone want to clone humans? Some reasons include:

• To help infertile couples have children
• To replace a deceased child

From a technical standpoint, before humans are cloned, we need to have a good idea of the risks involved. How sure can we be that a cloned baby will be healthy? What might go wrong? To evaluate the technical challenges to cloning, see Risks of Cloning.

Supported by a Science Education Partnership Award (SEPA) [No. 1 R25 RR16291-01] from the National Center for Research Resources, a component of the National Institutes of Health, Department of Health and Human Services. The contents provided here are solely the responsibility of the authors and do not necessarily represent the official views of NCRR or NIH.