The National Institutes of Health defines therapeutic cloning as cloning an embryo only for the purpose of producing embryonic stem cells with the same DNA as the donor cell. Therapeutic cloning aims to create stem cells for the express purpose of experiments so that researchers gain a better understanding of disease and work to develop effective treatments for diseases in humans.
While part of the goal of therapeutic cloning involves learning more about molecular causes of diseases, researchers also hope to grow healthy tissues to eventually replace diseased or injured tissues. They also use the cells cloned in the process to test new therapeutic drugs. Still, researchers find some drawbacks to cloned cells because they see many similarities between cancer cells and stem cells. Stem cells have the ability to multiply indefinitely in the same manner as cancer cells. After a few cycles of cell divisions, these stem cells may acquire the same mutations that occur in cancer cells, ultimately defeating the purpose of therapeutic cloning. Yet, this connection between stem cells and cancer cells drives lots of research in therapeutic cloning for researchers who feel it is necessary to understand the value of stem cells in the treatment of human disease.