What is the first thing people say/ask when they find out you are transgender?

"Do your parents know?"
"How could your parents allow you to do this?"

Seems like it is hard for many people to realize that nobody can "allow" me to live.

"When are you gonna become a chick?" Or anything similar

So are you a boy or a girl? Is the question I get asked.

I have to admit that people were very confused about the way I looked.
I am FTM.
When I would dress half girl/boy people thought I was MTF. Kinda sucked until I was able to start affording my own clothes. Now I pass as male 100%.

"So... are you getting [wiggles hand suggestively]... 'the surgery'?"

Before I moved away and became stealth.

"Has everyone been asking why you picked Alex?"
"Nope..."
"So why did you?"

"What was your girl name?" (I Hate hate hate that question with a passion)
"So..how are you gonna..do it?".
"Are you sure? Your so young".

"What does your mom think?/Is your mom dealing ok?" And "Do you think this will make you happy?"
I am honestly fortunate enough to be surrounded by extremely supportive people. So far, the worst reaction I've received is some co workers ignoring it, but since legal stuff has started, they've been much better about it. I have no idea how I'm going to react when I inevitably hit negativity. Even when my mom wasn't being supportive about transition, she was trying to get me to counseling for my depression and gender questions. She was just concerned I hadn't thought it through enough (which, given how impulsive I am, is a legitimate concern).
And then, there's my brother. I told him last  year. He forgot. Asked no questions. Fat forward to July.
"Brother, I am becoming manly. Male pronouns plz."
"Huh?"
"I told you about this. I know I did."
"Oh, right. The trans thing. Is that an official thing now?"
That boy I swear.

I'm stealth, so no one asks anything because they don't know.

I don't currently tell anyone, though I am out in the trans community and nobody there asks stupid questions, LOL.  I had the opportunity to meet a young trans guy this week in  space where nobody else knew except his family. He passed great.  Someone did ask me whether he was a boy or a girl (he looks really young, younger than he is) and I said boy and that was that. 

There are people around me who probably wonder about me, because I have kids, and because I say my former partner was male, my kids have two dads... and gay men with kids that are my kids ages would be unusual at best.  Nobody asks and I don't offer.  Not their business.  And I can talk about my past without 'lying'.   Just not something I am going to disclose in casual conversation.

They didn't know I was trans at the time, but a few people lately have expressed disbelief that I am actually a guy and asked how old I am.
I've had one person I came out to ask about surgery and a couple ask if I plan to transition then.

Something alone the lines of "Hey I just met you and this is crazy but tell me about your genitals in explicit detail maybe right now and if you don't I'll cry and whine about how I'm just curious and you need to be nicer to me."  But yeah, it always comes back to the genitals "what do your genitals look like"/"have you had surgery on your genitals"/"will you have surgery on your genitals"/"do your genitals still work"/"will you genitals still work if you choose to have surgery on them" and on and on.

Usually I get asked about surgery. Like do I plan on getting lower surgery? Really not anyone's business.

The very first response I get is disbelief.

"No way! You're joking."

"But you look so much like a guy."

Then people ask. "Do you have a penis?"

Some guys I'm cool with asked "So when are you getting your penis?" and "How are you going to make a penis?". They asked this after knowing for a while. Mind you, we were in public around kids (we were in a subway). They continued to banter me even when I was obviously not comfortable answering those questions.

I think the best is

"so are you going to get THE surgery?" while pointing down below

Well, I'm stealth but a few people found out recently and they took it to mean I was MTF, either way the first question I got was "so did you have...it...removed?"

"So... How do you have sex?" Or "Are you and your husband staying together?" If they know both of us.

"Are you a boy or girl? Really?"

Oddly enough the only actual straight u question i've got after coming out has been "So.. what do you want us to call you? Like, do you have a name picked out?".

It's extremely weird. but my family kind of assumed it, my first serious girlfriend knew it before i told her, my friends didnt give a damn, ect. I never got much in the way of questions unless i asked people if they had questions, lol.

I really don't get asked much questions and if I do, it's mostly about the transition process in general and so on. The most specific question must be along the lines "so do you have to take those hormones for the rest of your life?" Well... obviously, especially now that my own hormone production has been eliminated lol.