@Jennythelib - You're right. When I was a teenager, I was on Retin A for my acne. The doctor (and my mom) made a big deal of asking if I was sexually active and making sure I knew about the risk of birth defects. My mom went so far as to offer to get me the Pill if I was thinking about having sex and said I wouldn't get in trouble for asking.
The thing with these acne medicines is that the people who most want them--young women--are also those at most risk for an unplanned pregnancy.