Q. Will using stems cells to grow replacement tissues or organs make surgery obsolete?

Scientists hope eventually to use the cells to create replacement tissues and organs for people who are sick or injured.

This raises a second possible therapeutic approach: that of using the fused cells themselves to make replacement tissues.

McCoy absently scratched the replacement tissue over the wound in his forehead.

Theoretically, the stem cells could in turn grow into virtually any cell type and serve as replacement tissue in diseases like diabetes.

That means stem cells might one day be used to generate replacement tissue for damaged organs and treat numerous diseases.

It might also allow replacement tissues to be made that are genetically matched to a patient, so they would not be rejected when implanted.

The surgeon will make another incision in the knee and take the graft (replacement tissue) at this point.

Then those cells, patients hope, could be turned into replacement tissue to treat or cure their disease without provoking rejection from the body's immune system.

Others say they may one day use stem cells to grow replacement tissues that are identical to the patient's own cells.