When I talk about stem cell science, it's usually in the context of goals in tissue engineering and regenerative medicine, especially as they apply to repairing the damage of aging. Organ regrowth, scalable production of large numbers of tailored cells, autologous cell therapies, and so forth.
There's a whole other side to stem cell research, however: making it easier and less costly to both understand disease mechanisms and test therapies in the laboratory. If researchers can reliably use therapeutic cloning - or other methods - to produce pluripotent cells from adult cells, then limits placed on the study of disease mechanisms due to scarity of cell samples vanish. This would be a great step forward:
Scientists have taken skin cells from patients with eight different diseases and turned them into stem cells. ... The stem cells were created by taking biopsies from patients with diseases such as Huntington's and muscular dystrophy.
By taking skin cells from diseased patients, returning them to their embryonic form before redirecting them to becoming heart cells, a greater understanding of how heart disease develops can be gained ... They can also be used to test drugs - potentially paving the way for more effective treatments.
The technology in this case is induced pluripotency rather than therapeutic cloning, the use of recently discovered genetic switches to reprogram cells into a stem-cell-like state. Diversity of competing methodologies is a good sign for future progress in any field.