I wouldn't worry about it. If it looks like a duck, quacks like a duck . . .
I did actually once have a girl once, many years ago, who I later found out had once (according to reports by others) been a man. That was in Bangkok when the scene was a bit more laid back than it is now. Not exactly beer-goggled but felt flattered (haha) how she and her friend competed in the 'bidding' when I pressed on price. In Thailand I believe most of them take out insurance to look like the "all American woman" and I have to admit they are probably the best TGs you'll see from anywhere in the world. The woman agreed to a short weekend break with me for free (in what used to be a nice quiet resort not far from Bangkok.) I paid for the bus or train, can't remember which, and the two nights at a cheap guest house near the beach.
Regular visitors to countries like Thailand know that the "I love you longtime" routine has a number of variations and not all of them hit you for cash (at least if you just love them and leave them). To her credit I have to say she was quite loyally devoted and tried to act like a civvy girlfriend (her idea of one anyway) and shared incidental expenses. I felt a little embarrassed that my sexual desire for her seemed to diminish to almost zero once away from the heady bars of PatPong. She had no Adam's apple or any other of the obvious traits. Back in BKK her friend, possibly annoyed at having "lost the deal" poked fun at me asking if I knew the girl I'd just been away with was a katoy. I think in retrospect now she probably was, but it doesn't freak me out. I think it is more down to whether you enjoy yourself with the woman (if she is to all intents, appearance and purposes a woman). Many TGs have a bad rep for attitude, but that can be a generalisation. Would I knowingly go with one like that again? No, but at 3am in Bangkok as a bit of a newbie it seemed fine at the time (and in this case no harm done.)