Look. This is getting cringy since you keep throwing the word "science" around. I'm a researcher in a genetics/neurobiology lab and I can't watch this any more. Twitter is like the worst possible format for an ad hoc biology/genetics lecture but let's have a go.
First: you know how in physics the bohr model of the atom is put in kids textbooks and later when you get to college they tell you that actually that was a simplified lie for children. Biology is kinda similar with the XY chromosome thing. Reality is way more complex.
There are people who are XY who were born with vaginas, who identify as women and who go through their lives living fairly normal female lives and only find out they have a Y chromosome when they have trouble conceiving.
There are people who are XX who are capable of Penis jousting. And there are plenty of people on the fuzzy lines in between who are xxy, xyy, xxx, xx but with an sry gene on their X or xy with no sry gene or xy with sry gene but with parts of their sex determining pathway broken
There are people who are born phenotypically apparently female who spontanously grew a Penis at puberty. And that is a tiny tiny slice of the phenotypic and genetic variation we can observe. When sexing genetic samples you'd think male vs female would be cut and dry. but no.
And then we get into the neurology side. Brains are weird things that have ideas about what shape the body they're in is supposed to be. People born with deformed hands with < 5 digits who have then lost the hand to accident develop phantom limb pain in fingers they never had.
Our brains are fully capable of believing we should have anatomy we weren't born with. Or shouldn't have anatomy we were. Which is important because most people consider their brain the most important bit ie who they actually are inside.
And brain development can be affected by a lot of things including hormone levels at various stages of development. But as mentioned, brains are the super important part for humans. They're the most central defining part of us.
Put another way you would probably still consider yourself male even if you lost your penis in a car accident. People who argued that you weren't male based on them categorising males/females based on presence or absense of Penis would be assholes.
If they tried to make you wear a dress and refused to refer to you as 'he' they would be assholes rubbing salt in the wound. Because your brain would still be telling you that the shape your body should be should include a penis.
