I ain't gettin' in the "is it" or "ain't it" fornication debate (that's been discussed ad nauseum) but I will comment on the posts that said that this type of talk was "adult only" or should be.
The problem with trying to make this an "adult only" talk is that the Society doesn't have a system for "children only" or "adult only". They don't have Sunday School or Bible Camp or any other program for children or young teens. Everyone is thrown together all the time, every time. If it's good enough for the adults, it's good enough for the kids.
The Society claims that this is a better way of teaching Bible truths, but actually it's just another case of trying to be different for different sakes.
The Society claims that everything discussed at their meetings is family friendly as it is Bible based and for all age groups, thus no need for special classes due to age. One can argue whether children should be hearing discussion about sexual matters, but the Society does say it's better to be frank about sexual matters with children, which I agree with...to a point. But since so many in attendance are from all age groups, there is bound to be some in attendance that don't need to be present for such discussions.
I've heard people talk about the violence of the Bible. Indeed, if many of the stories of the Bible were made into movies, they would be rated R. Passion of the Christ was rated R (US) and that movie was based on the same material that children's Bible stories are based on.
The issue I have is that they'll say be frank about these discussions on one hand, yet on the other hand trot out that "be babes as to badness" scripture to counsel adults from enjoying any entertainment that is intended for mature audiences.
So it's okay for kids to hear this mature themed talk on sexual matters, yet it's not okay for a mature Christian to go to an R-rated movie that deals in adult themes. "Okay kids, we're gonna talk about oral sex. Be sure to pay attention to see what God hates. What is oral sex? We'll, when you're older you'll know." versus "No, we won't be watching The Graduate on TV tonight. It deals with adult matters, so I thought it best to adhere to the Society's counsel about being 'babes as to badness'".
But I guess trying to control one's sexual habits is the same as trying to control one's entertainment habits. "Be babes as to badness" applies to all JWs as if they were children. I guess it's okay to them to talk about these sexual matters because in the end they're condemning them, thus setting up the control early in children's minds about what is allowed or not allowed. Create a fear of these things and hopefully (in the WTS view of thinking) they'll grow up afraid to experiment with such "lurid" practices.