What is Gender?

A simple question to answer, yes? Perhaps if we still lived in a world were male and female was roles were limiting and clearly defined. Where men are seen as the providers, the protectors, the dominate in society; and where women are put in the roles of the nurturers, the supporters and the submissive. I'm not saying that they can't be any of those things, but let's be honest, we are far past these primitive notions of men must be the sole providers and that women cannot (or should not) hold a job or live independently (just a few examples). And, if we are being really honest, we can see that gender isn't as black and white or as simple as male and female. There is a whole community becoming more and more prevalent of gender non-conformists, transgendered and transsexual people. Weather you believe it is right, wrong or don't have an opinion on it, we can't ignore the fact that it is there.
Last week we had a speaker come to the house for our Urban Studies seminar to speak to us about transgender issues. So many questions were brought up that I had never even begun to think of before. Until Willie came to speak I wasn't aware of how little I knew about the transgender community. You often hear about "Transgender" when talking about the LGBT acronym, grouping it with three sexual orientations instead of dealing with it as a subject of gender identity, which is what it is.
This gets to the root of the question of what exactly is gender? I confidently can say I am female, but what truly makes me female? Obviously it must be more that just what chromosome I was given or what I look like. I believe it has to even go somewhat beyond the cultural expectations placed on my gender. These questions are hard ones to answer. Yes, I am a woman, but no, I do not want to be mostly defined by my femininity. I refuse to be held to certain expectations or roles because I am female. I want to be held to expectations based on who I am, not what I am. Though it must contribute, I don't believe I am who I am simply because I am female.
Now, to get even more confusing, what if a person doesn't feel as if they are the gender they are born? Essentially that is what a transgendered person is. We hear terms like "transvestite" or "drag queen/king", but don't realize that these are people who often simply "play" with gender. Yes, these people often belong to the LGB community, but fall more into the category of gender non-conformists rather than people seeking to become and belong to the opposite gender.
Interesting things to think about. How do you tell someone that they must love who they are if they feel as if every part of them doesn't belong to the gender they were born? How do you dismiss some one's feelings if they are uncomfortable going into their gender's bathroom? It is difficult for most of the population, having never felt these particular insecurities, to understand where people who feel this way are coming from. But, just because it is difficult to understand, doesn't mean it isn't a legitimate issue.
Though confusing, I'm glad I've been given these opportunities to be exposed to different members of the population regarding not just this topic, but many others as well. I hope that I can come to respect, even if I don't fully comprehend, others that are different than I am, no matter their differences.
Thoughts on this?