NCWISEOWL--Britannica and Grolier
http://www.ncwiseowl.org/zones/middle/index.htm

National Human Genome Research Institute
http://www.genome.gov/10001204

US National Library of Medicine
http://www.nlm.nih.gov/medlineplus/

Web MD
http://www.webmd.com/

Mayo Clinic
http://www.mayoclinic.com/

Genetic Disease Foundation
http://www.geneticdiseasefoundation.org/

National Institute of Health
http://health.nih.gov/topic/GeneticDisorders

DNA Learning Center
http://www.ygyh.org/

Genetic Foundations
http://www.kumc.edu/gec/support/