The terminology separates sex from gender. When we're talking about
gender all we're talking about is feelings. Your biological characteristics determine sex. A person can not change their chromosomes. They can change their gender.
What issue did you just raise other than your ignorance about the difference between sex and gender?
What Do We Mean By Sex and Gender?
Me and Yale school of medicine tried exclaiming that to you above. It could just be that you're too stupid to understand the difference.
The DNA that makes up you and your sexuality is also a mutation. We all evolved from single cell organisms who reproduced asexually through cell division. The only difference between the mutation for opposite sexual attraction and homosexual attraction is the frequency which it is found.
And do you know why men occasionally pick up trans women? It's because no one knows what chromosomes anyone else has. Sometimes people don't know what chromosomes they have. You aren't attracted to chromosomes. You are attracted to people who present a certain way. There are cases of people not learning until much later in life that they have different chromosomes than they initially thought.
What science? I linked to Yale School of Medicine. Why don't you give me the link to the place where you get your understanding from?