As already mentioned, its when you use stem cells to repair, or even replace damaged tissue/organs. What makes it less controversial is that you are only regrowing parts of a body, not creating a new person. That is called reproductive cloning, and its controversial because its unnecessary (there are no benefits to it, and it reduces genetic diversity) and also because some studies suggest an increased mortality rate in cloned organisms. Where the stem cells come from is controversial in both therapeutic and reproductive cloning - if the cells come from embryos then its controversial.
'A procedure in which damaged tissues or organs are repaired or replaced with genetically identical cells that originate from undifferentiated stem cells.' Basically they can grow cells to replace the ones that may be damaged or cancerous i think in the patient. I dont think changing the type of cell they use makes it different for those who are against it. I think if it saves someones life then it is a good use of technology.
