It really depends on the person. There is no actual "gay" voice, though we all know the sterotype you are referring to. I am a man who likes men(not gay), and I can't make that voice for the life of me. I also know straight people who have the exact voice in reference. I also know gay individuals who purposely alter their voice for added emphasis. I also know trans individuals who voices have changed something akin to this due to the hormone replacement therapy that they have undergone.
In the case of your voice naturally being like this, I don't think being gay is any sort of factor. You either have a voice like this naturally or you don't. If you happen to be gay and have a voice like this it's nothing more coincidence. Frankly, I don't see why a gay person would choose to have a voice like this--for many of them, they aren't open about their sexuality, so why would they willingly possess such an "indicator" so that people may poke fun of and ridicule them? I mean, if they'll call someone who is shown to be straight beyond a reasonable doubt(wife, kids, girlfriends etc) gay because of their voice and poke fun of them for that why would someone who is actually gay but not open bring that upon themselves?