Human cloning is the creation of a genetically identical copy of an existing, or previously existing, human being or clone tissue from that individual. The term is generally used to refer to artificial human cloning; human clones in the form of identical twins are commonplace, with their cloning occurring during the natural process of reproduction.
Although genes are recognized as influencing behavior and cognition, “genetically identical” does not mean altogether identical; identical twins, despite being natural human clones with identical DNA, are separate people, with separate experiences and not altogether overlapping personalities. The relationship between an “original” and a clone is rather like that between identical twins raised apart; they share all 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.
James A.Byrne – John B.Gurdon