Stem cell means cells that have the potential to differentiate into cells of different organs.
Stem cell therapy is still experimental. It is being studied for healing degenerative disorders or in diseases where the functioning cells of an organ tissue have died. They are unable to reproduce and thereby bring new cells to replace the old injured and damaged cell. The stem cells of the person are then developed into whatever special organ cell is needed and then infused so that they can replace the dead cells and do its function. It is one of the ways that Science is trying to conquer diseases and prolong life as such it is alright.
Affectionately,
Alok Da