Okay, apparently, once you come out you're expected to be able to answer any LGBT-related question. Here are a couple that I've heard a lot (and often wondered myself; I now have an opinion, but I thought I'd try to get the opinion of some people here): If someone gets a sex-change surgery, what gender are they? If someone is transgender (but has not had a surgery), is it impolite to use the pronouns that the person was born with? What pronouns do you use if someone switches between genders? Personally, I feel like a person can't change what sex they are (because it's genetics/biology), but gender is more like sexuality, because it depends on what the person feels. I also feel like no matter what body parts someone has, people should refer to them as whatever gender feels right to the person (or no gender, or whatever). Is that right?
Surgery doesn't change how they identify or are identified, nor is it even essential. That all depends on how they present themselves as.
Sounds like you've got it all down pretty well. Here are my own thoughts: If someone gets a sex-change surgery, what gender are they? Since gender is a mental thing, it can't be changed with surgery, so they're the same gender they were before the surgery. If they're MtF, that means their gender was female before and after, and if they're FtM, that means their gender was male before and after. That's why I like the term "gender confirmation surgery" for the procedure, a term coined by Dr. Loren S. Schechter (who defended the term in a very good article you can find here). If someone is transgender (but has not had a surgery), is it impolite to use the pronouns that the person was born with? Yes, because it invalidates their identity and enforces the gender identity that they don't want. Here's an extended metaphor I like to use. Say a women with the last name Lee marries a Mr. Johnson and takes his last name, so she's now Mrs. Johnson. Now let's say, years later, she divorces Mr. Johnson because he mistreated her horribly, and because she wants to put that part of her life behind her as much as possible, she changes her name back to Ms. Lee. To call a transsexual person by their birth-sex instead of their true sex would be like continuing to address Ms. Lee as Ms. Johnson after the divorce. What pronouns do you use if someone switches between genders? When in doubt, ask. In cases like that, if I haven't asked, I often find myself forgoing pronouns and using the person's name as often as I can. If that gets tedious, I just use the singular "they". Also, Yeah, that can happen. If it bugs you, it would probably be worthwhile for you to tell the people who ask you these kinds of questions something like, "I'm not an expert or anything. I'm just a lady who likes ladies. The only questions I know I can answer are the ones about things I've experienced; otherwise, no guarantees."
Silly expectations imo. Assuming you're talking about getting a different physical sexual organ, then they are their new sex. Because gender usually refers to social and cultural images of gender, not biological sex. Depends on the individual, but I think most would appreciate it if you made the effort to use the appropriate pronouns. The rational thing to do is to ask said person which pronouns you should use. People can, through a combination of surgery and hormone treatement change their biological sex. The thing is that biological sex is an objective thing, whereas gender is a social and cultural construct and therefore highly subjective and different per region and culture. A person should be called what they like to be called imo.