Stem cells: n. Undifferentiated, primitive cells with the ability both to multiply and to differentiate into specific kinds of cells. Stem cells hold the promise of allowing researchers to grow specialized cells or tissue, which could be used to treat injuries or disease. Stem cell research is controversial because the best source of stem cells is human fetal tissue. Harvesting the stem cells destroys the embryo, which many see as morally problematic. 1. What are human …showed first 75 words of 585 total…

…showed last 75 words of 585 total…cells not just in cell-based therapies, but also for screening new drugs and toxins and understanding birth defects. However, as mentioned above, human embryonic stem cells have only been studied since 1998. Therefore, in order to develop such treatments scientists are intensively studying the fundamental properties of stem cells, which include: 1) determining precisely how stem cells remain unspecialized and self renewing for many years; and 2) identifying the signals that cause stem cells to become specialized cells.