When I was a little boy, my mother was very active with Planned Parenthood. For a while she was on the board of directors.
That's where my book called Did The Sun Shine Before You Were Born came from. It ran down what sex was, how it made babies. It was pretty straight forward explaining that sex was what happened in bed when mommy and daddy loved each other. It didn't go into how much fun it is, how it can happen in all sorts of places without beds and how there are plenty of times when love has nothing to do with it.
My mother also taught a sex-ed class at a local private school. She'd come home at night with a box filled with replicas of the male and female anatomies, replicas that you could take apart to see all of the pieces that made up the larger contraptions.
In the another box she had samples of every form of birth control available at the time. As a 6-year-old I could not only name what each device or pill was, I could explain how it worked.
Condoms and diaphragms were simple to understand, I didn't quite get how pills and hormones worked, and I thought the idea of an IUD irritating the lining of the uterus was creepy.
Now, there are those who will tell you a 6-year-old is too young to know all of those things. I'm not sure why. I had no more urge to have sex than any other boys.
What I did have, though, was a great feeling of responsibilty. Once I did start having sex, I knew what I was doing (birth control-wise), I knew why to do it, I didn't have any problems asking and using, and I knew I had no excuse for ever coming home with scary news for my parents.
The frankness did lend itself to odd or awkward conversations, some unintentional.
Once in high school, my mother and I were driving somewhere on a rainy day. She asked me "What do you think about rubbers?"
"You know, rubbers, do you ever use them?"
"I guess not, I've never seen you putting them on."
"I'm talking about galoshes."
Of course, mom, of course.