What are stem cells and how will they impact our future? Stem cells are unspecialized cells that renew themselves for long periods of time through cell division. By researching this subject, scientists are investigating the possibility of using these stem cells to treat diseases as well as understanding birth defects. Scientists first discovered ways of obtaining stem cells from mouse embryos more than twenty years ago.

After many years of observing and studying mouse stem cells, in 1998 scientists were able to isolate those of a human embryo and grow them in a laboratory. James Thomson, of the University of Wisconsin-Madison, led this discovery. These cells have three fundamental properties: they are unspecialized, they are able to divide and renew themselves for long periods of time and they are able to become specialized cells.

Embryonic stem cells are derived from embryos that have been fertilized in vitro and donated...