I remember when I was about 10 years old, I tried to buy some airplane glue from a local hobby shop in Sacramento, where I grew up. "You have to have your mom or dad's permission," said the clerk. I couldn't figure out what that was all about. It wasn't like I was trying to buy cigarettes or beer. But it turns out that even back in 1964 we knew that there were some things that don't seem like drugs that could have dangerous effects when not used as intended.
What does substance abuse prevention really mean? What are we trying to prevent? The most obvious answer is that we are trying to prevent first use of a chemical substance. In fact, that's a great goal. But then does that mean we forget about the kids that have already tried something? And why do we care about preventing some 14 year old kid from trying beer or marijuana? After all you might say, "I did that and I turned out just fine."
Since the 1940s, our knowledge about what is safe and unsafe for anunborn child has increased exponentially. We've known for a long time that pregnant women shouldn't smoke cigarettes at all. And the standard for drinking is, "There are no safe levels of alcohol during pregnancy."