I do not believe you are a pedophile. As you said, you are not sexually attracted to kids. I don't think this is anything to be afraid or ashamed of bringing up to your therapist if you have one. This sounds more just of an attraction to the "wrongness/kinkiness" of incest, not the age of the daughter/son. That is certainly normal for many people. Your fear is understandable, but you know that because it worries you so, and you don't want to do wrong with your own kids, that, should you have them, you never would do anything with them. if that makes any sense....