How do I know if a therapist supports trans people?

Hello! I'm sorry if this isn't the right place for this question. I started therapy recently with a therapist my dad picked out. I'm trans (ftm I think, he/him, idk if this matters), and I wanted to talk to him about it. However, I don't know if he is accepting of/supports trans people. I haven't been going to him very long. He mentioned during a session if I wanted to ask him any questions before telling him something (to like gain trust/see what he knew about a certain topic) I could, however I have absolutely no clue what I could ask that wouldn't immediately out me. For example I think asking "have you ever worked with any trans people" or even "have you ever worked with any lgbtq+ people" would immediately tell him something. I've thought of asking "how open minded are you" but I feel like that's also not a good question to ask. Does any one have any tips on how I can figure it out? What questions could I possibly ask beforehand? If there's anyone who's come out to a therapist, how'd it go?