The website of ETR Associates http://pub.etr.org in
the U.S. offers a large amount of leaflets, books,
videos and other forms of material for health education,
including sexuality education, for fee. Materials are
published English and Spanish. A lot of educational
material is evidence based, and this is one of the
important advantages of this website. Start with
"Search by" and "Browse" options.
E.g. if you want books on birth control look at: http://pub.etr.org/Search