Calvin Klein was doing ads featuring adolescents in sexually evocative poses (sound familiar?) way back in the early 90s. My favourites have to be from the Marky Mark and Kate Moss campaign of 1992. Shot by Herb Ritts (who also did the MJ video mentioned by Tina below) in signature provocative black and white. A minimalist look that became synonymous with the brand and the era. I think the less is more ethos is particularly poignant in today's climate.
especially love the crop top for boys look!
Here's the tv commercial…SMOOTH