Hormonal
People are male or female. However, that is not what we are talking about in this challenge. We are talking about Gender identity which is defined as follows:
Gender identity refers to a person’s deeply felt, internal and individual experience of gender, which may or may not correspond to the person’s physiology or designated sex at birth.
I think this is an important distinction to make. Regardless of how you feel about it, there is only Male and Female. Just because this is a fact, it doesn't negate your feelings about it, and I think that's also an important distinction to make.
Our feelings are highly subjective to our hormonal state, whatever that is. We each have testosterone and estrogen flowing in our bodies and the levels of each have a tremendous effect on how we feel about ourselves and those around us.
If you ask someone who is attracted to the same sex, they will tell you that it feels normal to them. They will also tell you that they didn't choose to be attracted to the same sex, they just are. There is some physiological reason for it. If you feel like you are a boy trapped in a girl's body, there is some physiological reason for it. If you feel like you are a girl trapped in a boy's body, there is some physiological reason for it. The right approach should be to identify the physiological reason for it and correct it, not to change physical genders. Changing physical genders would be like treating a symptom, it doesn't correct the problem.
I know what you are going to say, but it FEELS normal to me. I know it does but if we correct the physiological issue, it will change what feels normal to you. I know what you are going to say next, but I don't want to change who I am and to that I say, YES YOU DO! Your feelings don't match your body and you want that corrected. So, correct it the right way, not the way that is just going treat the symptom and not really fix the problem.
My own experience with gender is pretty unremarkable. I have always been a boy. However, I did not feel the desire to act like a stereotypical boy. The reason is because I have low testosterone levels which indicate there may be a medical issue I need to correct. That doesn't mean I acted like a stereotypical girl though, I still acted like a boy, just less stereotypical. It also means that women were not attracted to me all that much which is a biology thing. Studies show that women are attracted to men who have more testosterone. But I guess that's a different topic.