Stem cells can be found in different places. And just where you get your stem cells from can make all the difference as to their potential.

1. Embryonic Stem Cells: Using a donated human embryo, scientists are able to extract the blastocyst (inner cell) from the 4-day old embryo. This is then cultured for about six months in a Petri dish until a cell line which contains millions of stem cells, is produced. Embryos are usually obtained from a donor who has given their informed consent that their embryos, originally created for IVF but are now no longer needed, may be used for stem cell research.

2. Bone Marrow: Bone marrow is the spongy material you find inside your bones. Contained within bone marrow, however, are stem cells. In fact, aside from cord blood, bone marrow is the richest source of adult stem cells. However, bone marrow stem cells have matured and therefore are more restricted as to what type of cells they can differentiate into. Moreover, normal environmental exposures and toxins have likely affected these cells. As a result, their use is more limited. Bone marrow transplants have been used to treat blood disorders, immune system disorders and genetic disorders.

3. Peripheral Blood Stem Cells: These stem cells also fall into the category of adult stem cells. Peripheral blood refers to the blood circulating in your system. Although this isn't the richest source of stem cells, peripheral blood stem cell donors can be administered growth factor drugs to help increase their number of stem cells. When donating the stem cells, blood is withdrawn from the body and stem cells are separated from the blood before the blood returns to the body. While this method of donation is simpler than bone marrow donation, there is a greater chance that the recipient will have complications, like graft vs. host disease.

4. Cord Blood Stem Cells: Cord blood stem cells hold great potential in treating a wide number of diseases and disorders. Cord blood stem cells are actually much more primitive than bone marrow or peripheral stem cells. These stem cells are taken from umbilical cord blood shortly after birth; once the umbilical cord has been cut, a nurse or doctor can drain the blood from the cord. This blood can then be frozen and stored privately or donated to public cord blood banks. When it is needed, the stem cells are thawed and ready to use in stem cell therapy.