I'm currently of the opinion that anything that happens in the bedroom of consenting adults is fine if it harms no-one. You've got to follow your heart, no matter where it leads. You can't say in your mind, "today I will love this person and not that person". It happens in the heart not in the head, and it happens whether you want it to or not. Society's bigotry and prejudice will ease and gradually diminish, I think. Some people love a person of a different race, or a different religion, or a person of the same gender, or a closely-related person. Love has a way of overcoming the artificially constructed barriers of society. Look, if two people really love each other, if they are willing to make sacrifices for each other, if their greatest joy is in being together, doing happy things together, if they inspire each other to be a better person, if they help each other, and take care of each other, then tell me, what the hell does it matter if they have different colored skin, or if they have the same genitals, or if they are closely related? And on the other hand, there is a lot of confusion and suffering from girls who grow up and leave home, and spend years searching the world for their true love, never realizing, because of society's prejudice, that he was just in the next room the whole time.