Society doesn't define men as being sexualised by wearing revealing clothing, but by performing feats of strength and general macho bravado.
Women on the other hand are seen as sexualised by wearing revealing clothing.
Stereotypical, yes, but that's kind of the point.
I'm not sure if its so much rebellion as the feeling of entering adulthood, and an undefined need to be 'grown up'. Since most of the adult world centres around the pursuit of one thing its only natural that children should be pushing to be seen in that way.