I just want to say that middle school was confusing and probably caused me to grow up too fast (or at least, to TRY to grow up). With that in mind, I think it would be very difficult to identify an appropriate period in a child's school career when they could be introduced to topics such as sexuality, especially when sexuality is discussed in ways that are not "hetero-normative." Maybe elementary school wouldn't be such a bad idea? 4th or 5th grade?
I suppose it comes down to questions about maturity and readiness. But I know many adults who are embarrassingly immature when it comes to sexuality as a social/political issue. I actually heard a teacher use the word "faggot" the other day, without missing a beat
I can't see kids talking about sexuality in a mature way when they're raging through puberty, and by high school the negative connotations in question are likely to have become at least somewhat solidified. This makes me think that towards the end of elementary school could maybe work...what are everybody else's thoughts? If you're going to teach about sexualitIES, when on earth are you supposed to do it?
Of course, this brings back up the tricky problem of parents and (vs.) teachers. Whose responsibility is it to teach about certain aspects of life?