Non-profit organization providing accurate, medically reliable information about sexually transmitted diseases (STDs).
http://www.ashastd.org/

Enables people to make informed choices about their sexual lives and to receive care, counselling, diagnosis and treatment.
http://www.ippf.org/

Providing easy access to sexuality information, education, support, and other resources.
http://www.sexualhealth.com/

Facts about sexual health with articles about puberty, menstruation, infections, and just about everything else you wanted to know, for guys and girls.
http://kidshealth.org/teen/sexual_health/

Supports a multidisciplinary approach to the treatment of sexual health issues and serves as an educational resource for individuals and healthcare professionals.
http://www.twshf.org/