We remove children from anything that is sex related, including talks and photos. When I think about it, it seems deeply and morally wrong to not do it.
When I first thought about that, I thought that it might be because we don't want to encourage them to become sexual. But we also don't want them to be violent, and no one thinks it's wrong to send a 5 year old to a martial arts class. For any other aspect of life, we let them, to some degree, experience.
That made me think that it might be something more than cultural. Of course the definition of "child" may vary depending on the society, but not the moral code of that ruling.