But what are stem cells? Stem cells are a special kind of cell that have the ability to divide indefinitely and have the potential to give rise to specialized cells (that is, any cell of the body). Stating it in scientific terminology, the defining properties of stem cells are-
          They are not terminally differentiated but determined.
          They can divide indefinitely.
          When they divide, each daughter cell has a choice: it can either remain a stem cell or take on a course leading to terminal differentiation.

          The job of stem cell is not to carryout differentiation function, but rather to produce cells that will differentiate. Consequently, stem cells have a non-descript appearance, making them hard to identify. But this is not to say that stem cells are alike. Although not terminally differentiated, they are nevertheless determined.