On the original topic: 15 years ago, I read step-by-step, year-by-year instructions for parents in re sex education of their children. I believe they were put together by AASECT :: American Association of Sex Counselors, Educators & Therapists, which is the professional organization of sexual health specialists in the US. I do not see the instructions immediately visible on the website now, though, but I am sure they are somewhere and have been improved and enhanced in the interim. They started with diaper changes.