Re: Is "Are you a boy or a girl?" really about genitals?
I think there are slight differences in the question depending on how informed or accepting a person is. For example, when I think about wondering whether someone is a boy or a girl (or other) I do wonder so that I am able to be accepting to which types of social scripts they typically prefer. Although there may be people who wonder this who are not trans or LGBT, due to their potential lack of awareness, it's less of "what does this person prefer" and more so "what is correct for me to say". I think this is because a lot of our views on gender are still very much not centered around the person we're referring to and are more centered around what is "correct language" for the person who is speaking. And often yes this does get reduced to genitals because many people simply don't acknowledge trans people and have therefore taught themselves that "to avoid being shunned socially myself, I must teach myself to quickly identify secondary sex characteristics so that I may be able to assume someone's primary sex so that I know how to correctly socially identify them in case we end up interacting."
Also, LGBT people have adjusted the language of this question to be accepting of everyone's feelings rather than going by a strict gender binary code-- "what pronouns do you prefer?" Versus "are you a boy or a girl?"
As for AssassinKat's comment about children, I believe that is accurate though because children still often view themselves overall as learners. When they are unsure of something, they typically don't question why and simply ask to listen and learn and accept so that they may catalogue this information to use later for their development. However, as adults, be typically grow beyond this stage and start making correlations and assumptions to just go by social rules-- we realize "all people I call "he" typically are born with male genitalia, therefore if I see someone who I believe has been born with male genitalia based on their secondary characteristics, it's safe for me to assume that they go by "he" so that I don't look like an idiot."
SO, then when trans and nonbinary people talk about getting in arguments or confused conversation with someone who insists they are a certain gender, it's because that person feels threatened, as thought they can no longer trust the instincts they spent years learning, and cannot believe how their own logic has failed them and made them look stupid, so they get defensive.
♪ ♫ ♪ ~ Deer Prince Kipp ~ He / Him ~ ♪ ♫ ♪