I think if you really want to learn more about the topic, one good place to start would be to read through the TransGAF here on GAF. You'll find stories from people about what they've gone through, why they made the decisions that they've made, and the search to figure out who they really are.
I don't at all look down on people who don't understand this topic, because it can be very complex and is something that still isn't out and public a lot of the time. The problem, as I see it, is that as of now what is assumed is that "penis = boy, vagina = girl".
That would be fine if that's what made people who they are, but it isn't. I'm going to assume you're a male, and forgive me if I'm wrong in assuming that. Are you a guy because you have a penis? What I mean is, is that the entire reason you'd consider yourself male? My guess would be probably not. You're probably a guy because you have a penis, AND because you feel like a guy, relate to being a guy, think like a guy, identify yourself with a guy, so on and so on.
What happens sometimes is that, for some reason, not all of those aspects are true. You have somebody who is born into a male body, but then they don't identify with being a guy, they don't see themselves as a guy, they don't relate to being a guy, none of that. For all of those things, they instead feel like and see themselves as female. Or, you have somebody who is born in a woman's body, but does have all of those feelings of identifying with being a guy, thinking like a guy, so on and so on.
I think the first step to getting better at dealing with gender issues is then asking ourselves what is more important about a person: who they are physically, or who they are mentally/emotionally. Now, I think most would say the latter. Is Stephen Hawking who he is physically, or who he is mentally/emotionally?
If you really want to give the topic some though, ask yourself a few simple questions as a start. If you are a guy now, but tomorrow woke up and you had a woman's body, which gender would you relate with? It's a simple question, but really answers a lot. If you suddenly had a woman's body, would that make you a woman, or would the fact that who you are is male be more important than that? Or look at it in another, somewhat sillier way. If you take a Toyota Prius, take the outside body off, and put on the chasis a Ford pickup body, what kind of vehicle is it? Is it a Toyota, or a Ford? A car, or a truck?
If we can say that who a person is is who they are inside, not outside, then we should allow ourselves to say that a person who is male physically but in every other way identifies with being female may indeed be a female. I know how hard it can be to accept that, because we have it so ingrained in us that the equation for what gender you are is as simple as a check of the crotch. But again, if we're then smart enough to understand that there's far more to being a human being than that, then we need to start to accept that life can't always be explained by such simple answers.
