There is an interesting article from an american journal of psychology that has some interesting things to say about gay men's sexual roles. I will try to track it down but the gist of it is that while some gay men are 100% 'top' and others are 100% 'bottom', the gay men with the healthiest attitudes to sexuality are those that identify as 'versatile' (enjoy both). 'Tops' often struggle with internalized homophobia, and find the act of being penetrated by another man emasculating. 100% 'tops' are the most often of the three types to be in the closet. 'Bottoms' were found to be the most likely to have gender confusion and use sex as a way to counter low self-esteem (much the same way some women use sex to feel loved). 'Versatile' men were found to be the most 'loud and proud' with their sexuality and enjoy the highest levels of self-confidence, self-esteem, and higher levels of self-worth. Of course I am talking in generalizations but this was something that held across many different men identifying as 't', 'b', or 'v'.
It isn't some crackpot article but a researched scientific journal article and personally I found a lot of truth in it.
I identify as 'versatile' as do many of my friends who are in relationships. If you both have the same anatomy, why would you limit yourselves to what could be seen as 'heterosexualizing' a gay relationship. On that note, there is so much immaturity in younger gays that I have known (college-age guys) that there really is this sort of heterosexualization of homosexuality. 'Tops' are more masculine, 'straight acting' guys, whereas 'bottoms' are the effeminate queens at the disco. This is a very limited way to see something so complex as sexuality. I would say I am quite 'masculine' but went through a stage of being almost exclusively a bottom simply because I had never felt my prostate stimulated in such a way before and I really enjoyed this newly discovered part of body (note to straight guys, ask your girlfriend if she's willing to help you find your own g-spot!) But then some primal instinct kicked in and I just really needed to pump my dick into someone! Coarse but true.
Also just as a quick aside, remember that not all gay men engage in anal sex so being gay does not mean you have to identify as ANY of the three sexual roles.