Cloning is the process of creating a genetically identical copy of an organism. There are several types of cloning including reproductive cloning to create an organism with identical genetics to a donor, therapeutic cloning to create stem cells for medical research and treatment, and productive cloning to create selected organs or tissues. Therapeutic cloning involves transferring the nucleus of a donor cell into an egg cell to produce stem cells that can be used to treat degenerative diseases like diabetes, Alzheimer's, and Parkinson's. Stem cells have the potential to differentiate into many cell types and are a promising area of research for regenerative medicine and disease treatment.