When you strip gender away from genitalia, brain structure, social and gender roles, masculinity/femininity, sexuality, chromosomes, and everything else that is associated with it, what remains?  What is it that makes you know "I am male" without defining it through these terms?

Wait, do we need to do that? Lol you just covered all the bases. Are we even people if you strip away all those things?

Anyway, dealing with these hellacious post-tubal period cramps without crying is what makes me a man.

I was about to say something similar - you've already taken it all away by listing all of that. We're just humans then.

Seriously though, without the scientific stuff (the physical anatomy, chromosomes, etc.) then it's all society and personal viewpoints that define what is man and what is woman. The baseline starting point are the physical differences though.

So your question should be, do you want to go with with what most of society accepts as man, or do you decide on your own what is a man?

Agreed, take away all of that and I think we're just humans.  But otherwise...I just know.  There's no good way to explain it, it's just how I feel.  For myself, it's not really necessary to define the reasons "why".  I just am, and that's that.

Sorry, I don't think I phrased it well.  This is stemming from me thinking about how to explain to my parents why I need to be male rather than a masculine woman.  The people in my life generally don't follow gender roles, and there would be no repercussions if I were to be a woman living a stereotypically male life.  Given this, I'm trying to break down what it is that is mentally driving me to live this same life as a man.  I'm basically just trying to figure out how we feel our gender without social or physical constructs. 

I don't think you can separate it from the brain. I think it's how your brain is wired that makes you man or a woman.

Self identity. It's innate.

the inner felling of belonging or not belong.

Nothing is technically needed to be a man. Personally, I place a heavy emphasis on body awareness/or just generally self-awareness. Brain structure plays a huge role in determining how a person understands themselves and their own identity, whether that person is trans or cis. I would say that brain structure is really the only tangible relevant thing in your list as far as what makes a person male, female or something else entirely. If we take away brain structure, the ultimately the understanding of the self as a particularly sex would not exist. Chromosomes even in cissexed men can be anomalous. Genitals even in cissexed men can be anomalous. Social gender roles change drastically between cultures and time periods. Masculinity/femininity are dependent upon culture and are extremely abstract concepts. Sexuality has nothing to do with a person's sex. Brain structure is the only thing that allows a person any awareness of sex. We would not be men/women and everybody else without it. If we look at the animal world, in many species interaction according to sex is extremely varied and not as rigid as it is among humans.

I'm a guy because I am aware of myself as a guy. In the end, cismen are "men" because they are aware of themselves as men, whether everything adds up to the normal social and biological expectations or not (and they don't always do). And what allows us to feel aware of it is brain structure.

And just to add, I understand wanting to trip being a guy away from all the superficial/physical/gender role stuff. It's something radical feminists as well as right wingers use against us as trans people. "Well if you 'liberal types' don't believe in gender roles then why 'change sex'." My response is and has always largely been that my maleness is completely separate from my interests, my social roles and so on. For me it is just about always having understood myself as a guy. It's not about living up to the stereotypes of what a guy "should be" in western culture.

"I am what I am and that's all that I am." I'm male because. No reason, just because. I feel male on the inside, so I am male.

But, I understand your desire to find a way to explain it to parents. When it comes time for me to explain it my dad, I am probably just going to have to tell him that I undergoing medical cosmetic processes to like my body more. If I try to explain it, he will pull out the fact that I wore dresses and bras and I really don't want to have to resort to explaining that I did it because of him and so on.

If we take away gender structures and roles in society, then really we are just humans. Take away the brain structure and we are just animals. Although, sometimes I would kill maim for the power that certain frogs have to change physical sex.

Berserk is spot on.

Cisgendered people don't have to explain their cis-genderism to us, why should we have to reason it out with them? I am that I am.

This is what kept me going all those years 

To put it very simply, if you asked a cisgendered person what makes them their gender, aside from their physical body and people's perception of them, what would they say? Transgendered people can answer the question as well since it's independent of the physical world. If I were to answer that question, I would say that it's metaphysical, and something that is just in us. I relate to other males, and feel like I empathize with them. It's just who I am beyond the constraints of the world's physical impact on me.