I have longstanding trust issues with women, so I chose a male therapist. I was hoping he was gay, too (because I am), and he was. (I had good reason to expect that he was gay because I had read an online description of some of his areas of expertise, and I saw that he covered all sorts of queer issues and practiced in the gay part of town.)
Even without my trust issues, I probably would have preferred a gay man. He gets both my gender and my sexuality on a fundamental level. It's awesome.