This thread has a few groups arguing different things.
Group A says, it's in real life, why not add it in DF.
Group B is clearly pushing a political agenda, and wants to pick and choose very current beliefs about the subject to push their politics on others.
Group C says homosexuality is offensive to some, keep it out.
I agree with the idea that it could just be another variable, just like in the sims. There's marriage in the game, so if there's gay dwarves, why the hell not let them marry eachother.
I also agree that it really wouldn't matter at all right now, except for the people who want to push their politics, and see "Gay" under the dwarf's description.
If you're going to have it as a personal detail, and dwarves can not like other dwarves for various personal details, then this sexuality should be the same.
Some dwarves don't like big noses, some don't like long hair, some don't like gay dwarves, some don't like light skinned dwarves. OR just don't have dwarves dislike any other dwarf for any reason. Whatever.
It's random, and it's a game. If you want to just pick and choose these details, until they just make the dwarves form the world you want to see in real life, you're just trying to push politics.
If you just don't want gay dwarves in anyone's game, you're just pushing politics.
My opinion is, there's no framework for romance anyway, so it's completely pointless at this time. When romance is added, go ahead and have some dwarves randomly homosexual. I just don't want to end up with a fortress where I can only kill off the white, straight, male, adult dwarves, because killing off other ones would cause controversy. Please don't make me play PC fortress.