Human cloning. Conceptual computer artwork depicting a hand scattering human embryos onto a field of DNA (deoxyribonucleic acid) code. DNA is made up of four types of acid base: thymine (T), adenine (A), cytosine (C) and guanine (G). DNA contains all of the genetic information needed for an organism. Cloning is a process whereby an organism may be copied exactly by implanting its DNA into eggs from the same species. Theoretically, it would be possible to produce unlimited numbers of identical copies of the organism. However, there are many ethical and practical problems associated with the technique.