In April of 1998, scientists from the University of Colorado School of Medicine reported that they had successfully used cloning as the first step in the successful treatment of an animal form of Parkinson's disease. Led by Dr. Curt Freed, the researchers used the same technique used to create Dolly to create cow embryos. After the cow embryos had gestated six to seven, the scientists isolated nerve cells with the capacity to produce dopamine, the missing chemical in the brains of patients with Parkinson's disease. The nerve cells were then transplanted into the brains of rats with the rat form of Parkinson's disease. The rats' neurological symptoms improved after the nerve cell transplants. Nerve cell transplants of fetal human cells have been used with variable success in human patients with Parkinson's disease, but this technique, if applicable to humans, holds some promise for greater success.

Another early step in the possible use of cloning to treat human disease has been reported by the company that helped to create Dolly. This group created genetically engineered cloned pigs. Pigs are potentially good sources of organs for human transplantation needs (indeed, pig valves are used routinely to replace certain damaged human heart valves). The scientists are hopeful that their ability to alter the pigs' genetic structure and yet still produce healthy piglets is a first step in producing pigs whose organs, when transplanted, are less likely to be rejected by the human immune system. Though this work is also quite preliminary, it also holds future promise.