Image generation models are perfectly capable of mixing different concepts to create images of things they're incredibly unlikely to have seen during training.
That sounds like a hit-or-miss concept to me. Without logic that teaches the AI why a child and an adult look the way they do it would maybe sometimes get it right by chance and other times not. I do not see how one could guarantee an outcome with the logic of the generation models unless it understands biology or was trained on real people which advertisements have no shortage of. Advertisements lack nudity and would leave out details like a hymen.