I had occasion to sing a little song at a party recently, whereupon a trans woman who was present—let's call her "Deborah"—immediately asked if I was gay. (I'm not.) When talking with her later, mentioning that our mutual friend had been trying to convince me that I was trans (which kind of backfired, incidentally, but that's another story), she stressed that anyone who sang like me had to be either gay or a trans woman.
At the time, I thought that this was bizarre—like, that's not what those words mean! Gay men are men who are attracted to men; trans women were males who decided to transition. I'm a man who's attracted to women, which is not either of those things! Deciding that I must be one of those things based on how I sing is wholly unwarranted!
But I was wrong and Deborah was right. People on the androphilic MtF spectrum tend to have naturally feminine vocal mannerisms; people on the autogynephilic spectrum have a natural incentive to fake it. (And I do fake it.) With neither the inclination nor the incentive, normal straight men don't sing like me, and Deborah was exactly right to pick up on this, even if I think her ontology is ultimately flawed.