Since the development of the medium, inclusion in films of any form of sexuality has been controversial, and in the case of most nude scenes has had to be justified as being part of the story, in the concept of "artistically justifiable nudity". In some cases nudity is itself the object of a film or is used in the development of the character of the subject. In some cases, nudity has been criticized as "superfluous" or "gratuitous" to the plot, and some film producers have been accused of including nudity in a film to appeal to certain audiences. Many actors and actresses have appeared nude, or exposing parts of their bodies or dressed in ways considered provocative by contemporary standards at some point in their careers. Nudity in film should be distinguished from sex in film.