Human cloning is the creation of a genetically identical copy of a human being, human cell, or human tissue. The term is generally used to refer to artificial human cloning, although human clones in the form of identical twins are commonplace, with their cloning part of the natural process of reproduction.
Although genes influence behavior and cognition, "genetically identical" does not mean altogether identical; identical twins, despite being natural human clones with nearly identical DNA, are separate people, with separate experiences and personalities. The relationship between an "original" and a clone is rather like that between identical twins raised apart; they share nearly all of the same DNA, but little of the same environment. A lively scientific debate on this topic occurred in the journal Nature in 1997. Ultimately, the question of how similar an original and a clone would be boils down to how much of personality is determined by genetics, an area still under active scientific investigation. (See nature versus nurture and cloning.)
ACT also reported its attempts to clone stem cell lines by parthenogenesis, where an unfertilized egg cell is induced to divide and grow as if it were fertilized, but only incomplete blastocysts resulted. Even if it were practical with mammals, this technique could work only with females. Discussion of human cloning generally assumes the use of somatic cell nuclear transfer, rather than parthenogenesis.
In January, 2008, Wood and Andrew French, Stemagen's chief scientific officer in California, announced that they successfully created the first 5 mature human embryos using DNA from adult skin cells, aiming to provide a less-controversial source of viable embryonic stem cells. Dr. Samuel Wood and a colleague donated skin cells, and DNA from those cells was transferred to human eggs. It is not clear if the embryos produced would have been capable of further development, but Dr. Wood stated that if that were possible, using the technology for reproductive cloning would be both unethical and illegal. The 5 cloned embryos, created in Stemagen Corporation lab, in La Jolla, were later destroyed.
In 1978 David Rorvik claimed in his book In his Image: The Cloning of a Man that he had personal knowledge of the creation of a human clone. A court case followed. He failed to produce corroborating evidence to back up his claims; now regarded as a hoax.
Severino Antinori made claims in November, 2002 that a project to clone human beings had succeeded, with the first human clone due to be born in January 2003. His claims were received with skepticism from many observers.
In December 2002, Clonaid, the medical arm of a religion called Raëlism, who believe that aliens introduced human life on Earth, claimed to have successfully cloned a human being. They claim that aliens taught them how to perform cloning, even though the company has no record of having successfully cloned any previous animal. A spokesperson said an independent agency would prove that the baby, named Evá, is in fact an exact copy of her mother. Shortly thereafter, the testing was cancelled, with the spokesperson claiming the decision would ultimately be left up to Evá's parents.
On October 9, 2003, newspaper Le journal de Montréal published an article accusing Clonaid and the Raelian religion of maintaining an outright hoax in its claims regarding cloning a human baby.
In December 2004 Dr. Brigitte Boisselier, Clonaid's Chief Executive, claimed in a letter to the UN that Clonaid has successfully cloned 13 children, however their identities cannot be revealed to the public in order to protect them.
Human reproductive cloning also would produce benefits. Antinori and Zavos hope to create a fertility treatment that allows parents who are both infertile to have children with at least some of their DNA in their offspring.
Some scientists, including Dr. Richard Seed, suggest that human cloning might obviate the human aging process. How this might work is not entirely clear since the brain or identity would have to be transferred to a cloned body. Dr. Preston Estep has suggested the terms "replacement cloning" to describe the generation of a clone of a previously living person, and "persistence cloning" to describe the production of a cloned body for the purpose of obviating aging, although he maintains that such procedures currently should be considered science fiction.
In Aubrey de Gray's proposed SENS (Strategies for Engineered Negligible Senescence) one of the considered options to repair the cell depletion related to cellular senescence is to grow replacement tissues from stem cells harvested from a cloned embryo.
The European Convention on Human Rights and Biomedicine prohibits human cloning in one of its additional protocols, but this protocol has been ratified only by Greece, Spain and Portugal. The Charter of Fundamental Rights of the European Union explicitly prohibits reproductive human cloning, though the Charter currently carries no legal standing. The proposed Treaty of Lisbon would, if ratified, make the charter legally binding for the institutions of the European Union.
Current regulations prohibit federal funding for research into human cloning, which effectively prevents such research from occurring in public institutions and private institutions such as universities which receive federal funding. However, there are currently no federal laws in the United States which ban cloning completely, and any such laws would raise difficult Constitutional questions similar to the issues raised by abortion.
Currently therapeutic cloning is allowed under license from the Human Fertilisation and Embryology Authority. The first licence was granted on August 11, 2004 to researchers at the University of Newcastle to allow them to investigate treatments for diabetes, Parkinson's disease and Alzheimer's disease.