You're probably thinking of The Genesis Children (1972). I believe there have been occasional posts praising the score by Jerry Styner, though descriptions of the film haven't given me any incentive to check it out (basically sounds like Lord of the Flies but with a lot of emphasis on the nudity).
Please please please, do not watch this obvious pervert explotation film -- full of young boy nudity. Just be patient -- I'll make suites and spare all of you.
Wow, I didn't remember being the one who started a thread on this. I'm not sure where I read about the film having a great score. I think the film was made at a time and in a place where nudity, even at a young age, was considered more acceptable and not inherently equated with sexuality (as evidenced by the cover for the Woodstock Two album), but in the world we are living in now this seems incredibly naive and misguided. Looking forward to someday hearing the music tracks without the accompanying visuals.