This is because genes do not directly specify complex traits. Rather, genes direct patterns of RNA synthesis that specify the production of proteins that, in turn, influence the development of a physical or psychological trait. A clone of Dr. Evil might, if raised by Mother Teresa, be a really nice fellow or, if raised by Arnold Schwarzeneger, he might turn out much stronger than Dr. Evil. As an example of a complex psychological trait that people might want to use reproductive technology to control and about which we have some evidence, consider sexual orientation. Together, the popular conception of cloning and the widespread belief that sexual orientation is inborn suggest that a person and her clone will share the same sexual orientation.
Relevant evidence comes from studies of identical twins and sexual orientation.
The most recent such twin study, done by psychologist Michael Bailey of Northwestern University in collaboration with Australian scientists, found that approximately twenty percent of the identical twins of gay men and lesbians were also gay or lesbian. If sexual orientation were strictly genetic, we should expect identical twins to have the same sexual orientation. Instead, despite sharing the same genes and having almost the same upbringing, at least half of identical-twins pairs have different sexual orientations. However, clone born years after his genetic father would presumably be brought up differently than his father. He would thus be even less likely to share complex traits like sexual orientation and moral character with his father than would two identical twins.