A major disadvantage of cloning is the trivialization of life. According to Methods of Life, Dolly the cloned sheep was a major breakthrough in 1996, but many embryos were destroyed in the process. The same destruction of human embryos also occurs during human cloning.
According to the University of West Virginia, human cloning is also harmful to the clone. There is considerable risk in creating a clone, which can cause unforeseen health problems in an artificially created human. Furthermore, an adult clone's life expectancy is virtually cut in half, since they were created as adults without a childhood. Cloning may also cause tremendous damage to the psyche and emotional well-being of clones because they know that they are an artificial copy. A cloned person may feel as though they have no choice in their identity and future.
Cloning also has the potential to render the human race extinct, because it prevents the gene pool from becoming diversified. Mass cloning can dilute the human gene pool, preventing humans from adapting to new surroundings, interfering with the natural course of human evolution.
The University of Virginia also warns of the tremendous resources that cloning can divert from the medical community. Instead of devoting attention to curing major diseases, future scientists and researchers could simply create a new life instead of healing the sick and dying.