National Health Education Standards and Tools
From Advocates for Youth, a listing of links to CDC sexual health education resources, including a Curriculum Analysis Tool.
Scarleteen
Inclusive, comprehensive and smart sexuality information and help for teens and 20s.
SexPositive
"A shame-free sex education smartphone app from the University of Oregon Health Center"
(Links to Android and iOS downloads included!)
SEICUS
Sexuality Information and Education Council of the United States
Advocates for Youth
Comprehensive sex education site, with resources for professionals, students and parents.
Answer
Based at Rutgers University, is a national program to provide comprehensive sex education to young people and educators.
Religious Institute
Faith-based advocacy group for sexual education, reproductive rights and equality.