[quote]How does gender differ from biological sex[/quote]Your gender is the way your mind "feels" [for lack of a better term] and your biological sex is your chromosomes/sex organs. For an overwhelming majority of people, those two things match, and we aren't caused any stress/anxiety/etc by it. [quote]why go through all the trouble to change your body[/quote]Gender dysphoria is something most transgender people experience. It's a state of discomfort/anxiety/stress/etc caused by the mis-matching of their gender and sex. When you make your body match your gender, it alleviates those issues. One would think it would be easier to make your gender match your body, but we don't know how to do that at this time. [quote]but keep your dick?[/quote]Personal choice. Some trans people undergo sexual reassignment surgery. Some don't. I'm not sure what it is about being transgender that makes other people think it's OK to ask about someone's genitals.