How do you feel about a species with a genetic predisposition to be either homosexual or bisexual?

I'm currently writing a novel where I need a species of sentient, humanoid aliens. They are born with one of three genetic traits that influence how they interact with each other. I want two of the traits to be acceptable, but the third to be viewed negatively. I was thinking the third trait would be being genetically predisposed to be gay or bi. I'm leaning towards bi because it's more complex and I feel like it would be more interesting to write.