New Organs from Stem Cells?

Stem cells can make copies of themselves. A small number of stem cells can be used to grow a big collection of millions of stem cells, in the laboratory. If we can learn how to “tell” stem cells to produce particular types of cells (e.g. heart muscle cells, liver cells), we might be able to

• take a few stem cells from a sick person
  
• build up a big population of stem cells in the laboratory
  
• grow a new heart, or liver for the sick person.
  

Because the cells would originally come from the patient, the patient’s body would not reject the transplanted organ – this is a real problem for patients today, when their bodies don’t recognise a new organ and try to reject it.