I'm still trying to wrap my head around this whole gender concept. On the one hand, I agree with the idea that no one knows what it is like to be anything other than him- or herself. I am an adult male human, but I do not know what it is like "to be a man" in the general or categorical sense; I only know what it is like to be me. So it is meaningless for me to say that I feel like a man, or that I feel like a woman. (Thomas Nagel addressed this idea more broadly in his paper "What It Is Like to Be a Bat".)

On the other hand, I am not persuaded that there is nothing more to the idea of gender than stereotypes. I cannot help but wonder whether there is something deeper going on, perhaps along the lines of an archetype, and whether this is something more deeply seated in the psyche. However, whatever gender is, I don't believe it can negate the objective reality that there are only two sexes. No one is born in the wrong body; they are born in their own body (albeit a body that might have something wrong with it). I have no problem believing that some people very strongly feel that they are or should be the opposite sex from their biology; but what one feels does not change the biological facts. Rather, I believe that the gender dysphoria is a simplified self-interpretation of feelings which are associated in some manner with ideas of gender.

I am not dismissing the feelings, which I don't doubt are very real. And perhaps in some cases it is easier to change one's body to smooth over this kind of dissonance than it is to rework one's mindset and mental models. If an adult makes that choice, who am I to say they are wrong to do so? But the thing about feelings in general is that they need to be taken seriously, not necessarily literally.