Recombinant DNA cloning has been used since 1970 for lab study and research. Reproductive cloning creates an exact genetic copy of an existing being using their nuclear DNA. Therapeutic cloning, also called embryo cloning, is used to create cloned embryos for stem cell research to treat human diseases. The process of human cloning involves removing the nucleus from a donor egg, fusing the egg with a cell from the person to be cloned using electricity, implanting the embryo into a surrogate mother who would carry the cloned baby to term.