Biology
Trans women are real women. Trans men are real men. Non-binary people are non-binary. All of us are real and valid. There have been studies on the physical makeup of transgender people, and while many of them are inconclusive, most validate transgender people. Chromosomes and physical sex are not black and white. Intersex people are those whose chromosomes don't align with the typical xx and xy pairings. Most intersex people have ambiguous genitals. Intersex people are as common as redheads. The animal kingdom also validates transgender people, as many animals enjoy homosexual relations and even sometimes change their sex.