Interesting comments by all.
I agree with Kym and Farmer Rob's comments and so won't repeat them.
Exploitation is exploitation be it for the purposes of art, publicity, finance or sex. Children should not be exploited.
Electric Images - interesting points except I don't believe photography is singled out (except perhaps in this discussion) movies, videos, games etc of the types that you have mentioned are not acceptable to many either.
I wouldn't be happy for my children to be photographed and exhibited in such a way.