Gender comes from the Latin root 'genus' which means 'type', and you can certainly be a boy type or a girl type and be from either sex.
You cannot change from male to female or vice versa without an organ transplant, which are not legal, at least here in the U.S., for sex changes. They are mostly rejected by the receiving body, anyway.
If you were born with a dick, you have been born with the male sex. If you pay a surgeon to turn it inside out, it is now a deformed male sexual organ. Not a female one. If you were born female, to say, with female sex equipment, you have a uterus, and a vagina. Labia. Clitoris. Fallopian tubes. If you lose your uterus through hysterectomy, you have lost a female sex organ. If you have never had a female sex organ. You. Are. Not. Female.
You can be a girl. You can have a girly, girlish figure. You can have feminine traits. Be female-like. But you will never, ever be female.
That being said, traps are hot, so leave them alone. Let them be girls. (though they are factually not female)
Got some horrible slurry or both sexes? Born with extra hormones on one end or the other?
Congratulations,you're some degree of hermaphroditic. You're as close as it gets to transsexual.
Sex is sexual organ. If you can't grasp that, you're unintelligent in that respect.
And if you're telling 'transsexuals" the truth just to hurt their feelings, you're being a cunt. If you truly understand that they're mentally incompetent and you're picking on them for that as entertainment or to make yourself look smarter, you're being a cunt.
Everyone knows they aren't really female. Shut up and let them feel sexy. Honestly, who cares about pronouns? Call them what they want. It's like calling a homeless man 'sir.' Just be polite. As long as they aren't forcing you to call them male or female, it does not matter. You don't have to lie and the trannies can go about their merry way creating fantastic porn.
Just shut the fuck up about it already.