Ok, so maybe I'm a freak, but I actually prefer sex to violence. I mean, if I had to choose only one to have in my life, I know what I would pick! If my kids had to see one or the other, I'd choose for them to see sex. Why? Because violence sucks, and I hope they never have to go through anything as horrific as what is common in movies these days, while sex *rocks* and I hope they grow up to have lots of it. I'm not saying that they will emulate what they see, I'm just saying that sex is a natural part of a happy life and violence isn't.

Go sex!!! Yay!!
(Sorry, your description of PG-13 bugged me )
Anyway, I chose "R". I don't mind sex scenes (obviously) and understand that most fantasy written for adults is going to have its fair share of violence. My own writing is probably more PG-13, but my comfort zone is different for what I read as opposed to what I write.