I'm not sure about in England, but in the US, we consider "media" a singular noun, so the correct way would be to say, "Whereas the mass media glorifies sex, ..." The rest of it sounds good, though I think using "perplexed" and "confused" in the same sentence is redundant. Maybe change the last bit to something like, "and thus the children are unsure how to deal with their own sexuality." However, from an essay standpoint, make sure you explain what you mean by "adults", since it could apply to both parents and the people who operate the mass media. As it is, I don't know if you're saying that parents are responsible for confusing children, mass media, or both.