Potential Risks of Genetic Engineering and Plant and Animal Cloning ¥ By improving food production and food quality quickly, cloning might, in turn, encourage if not propel human population growth and the consequences (both negative and positive) that go along with a larger population. ¥ One concern about cloning is the impact it might have on the process of evolution . Evolution is propelled by natural selection acting upon genetic and behavioral diversity. Cloning reduces genetic diversity. Will this be an evolutionary problem? ¥ What are the dangers of developing new zoonoses (diseases transmitted from animals to humans)? (See for example, "Infection of Human Cells by an Endogenous Retrovirus of Pigs", by Clive, etal, in Nature Medicine , vol.3, no.3, March 1997.) ¥ What are the dangers of new deleterious prions (self-replicative proteins) evolving, and causing diseases similar to Creutzfeldt-Jakob disease in humans (or Mad Cow disease in cattle), and rapidly spreading? (For further discussion about prions and their possible threats in transgenic animals, see the dialog between Wills and O'Neil in the New Zealand Veterinary Journal , vol. 43, p.86-88, and vol. 44, p.33-36.)