Livre d'Or

Rocky Horror - oh good grief no, trans and cross-dressing are so not the same thing!

My approach is to start at the other end of the problem. You don't need to know what people's preferred gender identities are to make the things you say non-gender-specific. People have names, and we have the extremely useful words they and their. When you start thinking about your sentences, so few of them need to have he/she/his/her in them. Almost all can be constructed to use a name or they/their without sounding weird or awkward. e.g. "So, class, Sam raises an interesting point. How can we respond to their criticism?" "I was talking to one of my coworkers about this the other day and they said..." "When you look at the patient in this picture what do you notice about their arm?" "How do you think a patient feels when they go to their doctor and are told to lose weight?" "Sorry, what's your name again? Alex, right. Can anyone explain to Alex what's wrong with that argument?"

It's only part of the solution; it doesn't fix what pronouns other people use, and sadly interjecting "they" when someone says "he" is more confusing and less likely to get a useful point across than "or she". :-(