Well, it turns out that pregnancy WASN'T the worst thing that could happen to sexually active teenagers, and that disease got it's own set of civil rights, but that's another story.
When kids are given the information about the dangers of early sexual activity, and are taught ways tools to avoid it, many will. There are many adults who will fight against the kids being taught these skills, though, many times because they're couched in religious terms. Forget about the fact that they actually WORK, it's just that whole religion thing that gets some folks all riled up.
As one who grew up during this era (born in 1955,) I think you pretty well summed things up. I do think that in addition to the ‘free-love’ philosophy, that postmodernism caused an erosion in at least an intellectual agreement with the notion of true authority. As society became more postmodern, the mantra became, ‘If it feels good (to me,) do it.’ This has caused an erosion in sexual mores, civility, and many other areas.