Top: Kids and Teens: Health: Conditions and Diseases: Mental Retardation (2)
http://www.simiax.com//Kids_and_Teens/Health/Conditions_and_Diseases/Mental_Retardation/index.htm

Mental Retardation - Provides a definition, suspected causes, and what life is like for someone who is mentally retarded.

Fact Sheet: Mental Retardation - Definition, causes, diagnosis, and information from the National Information Center for Children and Youth with Disabilities.