Mine was a combination of the book, Dee's method of open communication, and a very liberal school district which taught intense sex ed from 5th>11th grade. When I say intense, I mean that, by 10th grade, we had to insert a diaphragm into a model for a grade! It was also co-ed, and concentrated on the correct terminology and exactly what happens without getting embarrassed. It was obviously a good system, because I graduated with over 700 classmates, and there had only been two pregnancies. As I so often say about sex ed, knowledge = power.
To this day, I get confused by sexual slang, but I can tell you all about what happens to the body (physically & emotionally) during sex and/or abortions and/or pregnancy!
Oh, the best part? We always had two teachers, a man and a woman. Years later, I found out that my female sex ed teacher was an ADPi!!