Well, technically the purpose of life is to reproduce. So I don't see why incest should be a taboo. But then, comes the society driven rules, or many would call it "morals," that are enforced on others by others.
Sorry I haven't been on for a while everybody, I've been busy with work, classes, test, studies, meetings, and programs these months so far. I will be able to finally be more active soon! Again sorry and see you guys soon!