Pretty much my opinion as well. I feel the same about drugs. As long as someone is being responsible about it, that is (generally) more important than how old they are. I know a lot of people under 21 who are responsible about drinking alcohol. I also know a lot of people over 21 who are very irresponsible about drinking alcohol.

Same can be said about teen sex. There are a lot of teens who are responsible about it, and there are a lot of adults who are irresponsible about it. Give them more options to be responsible about it and they will be more responsible. That seems logical enough to me, anyway.