My mom gave me one of many sex talks beginning in third grade. Sex sounded so gross that I didn't understand why ANYONE would want to do it. Later on, in high school, when many girls were getting pregnant she asked me this series of questions:
You had girls that got pregnant in your HS? As in plural?
We had some girl who got knocked up in a bathtub after the senior prom in the class ahead of us, and it was the most scandalous thing that rocked the school district in years.
Then I moved to VT and it was commonplace. It was pretty freaky.