What are the types and sources of stem cells?
Stem cells can be obtained from the following sources: • Embryonic stem cells: these are stem cells obtained from very early embryos (pre-implantation embryos, also known as “spare” embryos and “substandard” embryos) that are owned by infertile couples and produced from in-vitro fertilization. • Embryonic germ cells: these are stem cells that are harvested from aborted fetal tissue. • Adult stem cells: an example of an adult stem cell is the hematopoietic stem cell. The moral and ethical issues associated with embryonic tissue and fetal tissue are not a consideration in adult stem cell research. Hematopoietic stem cells are the progenitor cells of the blood components (red cells, white cells, platelets) and immune systems. These can be obtained from the bone marrow, circulating or peripheral blood and umbilical cord blood. These cells circulate freely in the fetal blood, and are believed to migrate shortly after birth into the bone marrow, where they actively multiply in unlimited amou
