Q: What is research cloning?

A: Research cloning refers to the production of clonal embryos for scientific investigation. The nucleus of a cell of an existing animal or person is inserted into an egg from which the nucleus has been removed, and the resulting entity is stimulated so that it starts developing into an embryo. Embryonic stem cells are then derived from that clonal embryo.

Research cloning is also called somatic cell nuclear transfer (SCNT) or nuclear transfer. Older terms that are still used, though infrequently, are therapeutic cloning and embryo cloning.

Q: What's the difference between "reproductive cloning" and "research cloning?"

A: The cloning procedure is identical up to the stage at which a clonal embryo is either used for research purposes, or implanted in the womb of a female animal or a woman. See the discussion of reproductive cloning.

Q: Has research cloning been successful?

In a number of mammalian species, clonal embryos have been produced and embryonic stem cells derived from then. Research cloning has not been successful in human beings. The successes reported in 2004 and 2005 by a research team led by Hwang Woo Suk were later shown to have been falsified. Hwang's papers were retracted by the scientific journals in which they had been published to great acclaim, and Hwang admitted to scientific fraud, embezzlement of funds, and ethical violations involving the procurement of women's eggs.

Q: Doesn't the development of embryonic stem cell therapies require the use of cloning techniques?

A: No. All currently existing embryonic stem cells have been derived from embryos that were created but not needed for fertility purposes. Many thousands of such IVF embryos are being stored in fertility clinics, and many people undergoing IVF treatment for infertility have indicated that they would be willing to donate their unneeded embryos for stem cell research.

Q: Why do scientists want to use cloning techniques to produce embryonic stem cells?

A: One use for research cloning, which is commonly cited but currently is very speculative, is the production of embryonic stem cells that would be genetically identical to a person in need of replacement tissues that could hypothetically be created from them. In theory, these replacement tissues would not be rejected by the recipient's immune system - a problem that may have to be resolved before embryonic stem cells derived from IVF embryos are used as replacement tissues.

Another proposed use is the creation of genetically specific embryonic stem cells - the so-called "disease in a dish" model. These cells could be studied for clues to the very early development of the disease in question, or used for efficient testing of drugs that might be effective against that disease.

Q: Why are some people who support embryonic stem cell research concerned about research cloning?

A: There are three main reasons for concern. First, efforts to produce cloned human embryos require large numbers of women's eggs. In order to retrieve eggs, researchers give women hormonal treatments to first "shut down" and then "hyper-stimulate" their ovaries, followed by surgical extraction of multiple eggs. This is a time-consuming and invasive process associated with potentially serious health problems.

Second, research cloning raises concerns because of the exaggerated and probably unrealistic claims of "personalized" therapies made by many scientists and advocates. If the many technical obstacles to such treatments were ever overcome, they would likely be enormously expensive, and thus inaccessible to most people.

Finally, because research cloning involves the same technique that would be the first step in reproductive cloning, effective oversight to prevent efforts to produce cloned humans would be required. Concerns about unauthorized efforts to clone a human being are heightened by the fact that laws against reproductive cloning have not yet been passed in many jurisdictions.

Q: Is research cloning legal?

A: Research cloning is legal in most jurisdictions. A few US states prohibit it, but others actively encourage and fund it. At the federal level, the US government will not at present fund research cloning, nor does it provide regulation or oversight of research cloning efforts.

Last modified June 30, 2006