Embryonic stem cells are derived from embryos. Specifically they are derived from eggs that have been fertilized in an in vitro fertilization clinic not in a woman's body. These cells are grown by transferring the inner cells mass into a culture dish that contains a nutrient called culture medium. The inner surface of the dish is lined with mouse embryonic skin cells to provide a sticky substance for the human cells to attach and they also release nutrients. after a few days the inner cell mass begins to grow and when this happens they are moved into several fresh dishes. This process, subculturing, is repeated many times. Embryonic stem cells as well as adult stem cells possess the following two characteristics: First, they are unspecialized cells that renew for a long period of time through cell division and second, is that under certain conditions these cells can be...