The Vanderbilt Kennedy Center for Excellence in Disabilities has created two toolkits, one for boys, and one for girls, that provide factual information about puberty. Topics include encouraging good hygiene, appropriate behavior, and how to deal with the body changes. The toolkits also suggest ways to approach these important conversations, especially with children with disabilities.
Each toolkit also includes a separate appendix that includes visual aids to help teach body parts, and social story images to help your child learn what appropriate behaviors are and where they are appropriate. Parents can decide what information and guidelines they share with their children.
Both toolkits and the accompanying appendices can be downloaded for free here: http://kc.vanderbilt.edu/healthybodies