If this is not possible, then the stem cells have to come from a donor. There are fewer complications if the stem cells come from a close member of the family. Alternatively, donor cells can come from a person with closely matched tissue types.
Therapeutic cloning could produce stem cells with the same genetic make-up as the patient.
Stem cells produced in this way could be transferred to the patient. Although human stem cells have been produced in this way, and used in research, there is no evidence that, as yet, they have been used to treat anyone.