Everything is natural as everything occurs in and results from nature. Asking is X unnatural is a pointless question. Whether or not something is natural has no bearing on anything whatsoever. "Natural" or "not natural" is a pointless line of argumentation. If you want to ask whether overprotective fathers are good or not then that is a good question.
Don't get me wrong, those wimpy types do exist, but I think there's an explanation for it. It seems like those type of fathers are against sex for the sake of pleasure, and believe in romance. I don't know what got into me. Mind you I still stand on my opinion, regarding an experience I had here two weeks ago, but I think I've change my attitude a bit, and understand it now.