Rogina,
I don't understand your comment to Teresa at all. I agree with Teresa, so I guess I don't have a good understanding of gender, either.
I was married for a long time. My wife and I had straight sex. Sometimes I was dressed. Still straight sex. After the divorce I've been with a few men. I was almost always dressed. That was gay sex. I don't think it makes it any less gay that if I was dressed as a woman, "felt" like I was a woman, imagined myself to be a woman, or performed like a woman.