Cells derived from a Fetus that retains the ability to divide, proliferate and provide progenitor cells that can differentiate into specialized cells. The embryo is referred to as a fetus after the eighth week of development. Once a fetal stem cell has been harvested, it has the potential to live indefinitely in the laboratory. Fetal stem cells can be isolated from fetal blood and bone marrow as well as from other fetal tissues, including liver and kidney.