For a concise overview, see the following weblink: Understanding Gene Testing. U.S. Department of Health and Human Services, National Cancer Institute. http://www.gene.com/ae/AE/AEPC/NIH/index.html
This website provides a good review of basic genetics and genetic mutations. See particularly the following sections:
The following web-site provides information about environmental causes of illness.
Trends in the Well-Being of America's Children & Youth, 1997 Edition. Office of Assistant Secretary for Planning and Evaluation, U.S. Department of Health and Human Services http://aspe.os.dhhs.gov/hsp/97trends/intro-web.htm
The following web-site identifies the key behaviors that contribute to the leading causes of death. Leading Causes of Mortality and Morbidity and Contributing Behaviors in the United States. http://www.cdc.gov/nccdphp/dash/ahsumm/ussumm.htm.