Stem cells are unlike other cells because they can regenerate and differentiate into various kinds of cells. Stem cells occur during embryonic development and also are found in the adult body. They show promise for treating many health disorders.
Identification
Most cells have specialized functions and are specific to certain parts of the body, such as blood, muscles, nerves and skin. Stem cells, in contrast, are unspecialized, but can generate new specialized cells.
Adult Stem Cells
Adult stem cells, also known as somatic stem cells, occur in small numbers throughout the body. They create specialized cells related to their specific location.
Benefits
Adult hematopoietic (bone marrow) and umbilical cord stem cells are used to treat some health conditions, such as scoliosis. They show modest benefit for certain cardiovascular and autoimmune disorders, according to a study published in the Feb. 27, 2008 issue of the "Journal of the American Medical Association" ("JAMA").
Embryonic Stem Cells
Embryonic stem cells, also called pluripotent stem cells, show greater potential for treating more health problems, according to the University of Michigan. These include type 1 diabetes, Parkinson's disease and spinal cord injuries.
Controversy
Embryonic stem cells are a source of controversy because collecting the cells requires destroying embryos. These embryos are about five days old and consist entirely of undifferentiated cells, according to the University of Michigan.
History
President Barack Obama lifted a ban on federal funding for embryonic stem cell research in March 2009, overturning a policy signed by president George W. Bush in 2001.
