I haven't studied sexuality at all, but I have a unique viewpoint. I am asexual by definition, which means a person who does not experience sexual attraction. Asexuality is an orientation that makes up 1% of the population in America. A lot of people think that asexuality just means you don't like sex - wrong. Asexuality does not include people who are averse to sex due to trauma, or have physical or hormone problems etc - that is sexual dysfunction, not asexuality. Asexuals are people with no traumas or dysfunction, who are just not sexually attracted to anyone, basically. We have a libido, but we prefer not to involve other people in our "activities", only ourselves, hehe. I just wanted to put that out there because a lot of people argue that there is no such thing, or we are just repressed, etc. Wrong.

In terms of dominant and submissive roles, it seems to be all over the shop. Being asexual means I can look at the world without the sexual veil over my eyes, so to speak. I have observed lots of relationships over the years, both gay and straight, and it seems to vary from couple to couple whether one is dominant and one submissive. Although I have observed a lot of gay relationships to have one a bit more dominant than the other, usually I think the masculine person seems to be dominant and the feminine person is a bit submissive. I do observe it in straight couples too but I don't see it quite so often. Ofcourse, I have not studied every relationship on the face of the planet, so I can't really generalise on that point. Its just a trend that I noticed in the little sample that I have observed over the years. Could be unique to my area, I don't know.

In terms of how sexuality is decided, I have no idea! I, myself, have always been asexual, however that is just me. On the AVEN forums, most of them claim to have been asexual since they were born. However I have heard about many people who were married and had kids and were well into their 50s before coming out as being gay or lesbian. It is possible they were always gay and just conforming to society's standards of "married, kids, a nice house and a dog" and then eventually got the courage to come out. But then I also hear of other people who just realised one day that they were gay. And then you hear about people who had had bad experiences with the opposite sex and swore off them for life, and started having relationships with the same sex from then onwards.

So in summary: who knows?!