"Science proves that gender is something that's ingrained in the brain and neurology backs up transgender people's brains matching their gender identities"
If transgenderism is brain-based, then why don't they do a brain scan, or
any kind of neurological testing on people seeking transition so they can prevent the patient from facing future struggles with detransition, including damage to the endocrine system and literal amputation/mutilation? Why do they dole out hormones and surgeries after hearing them say "I think, therefore I am" instead of doing a medical test? I don't know which brain studies he was looking at (you should probably get him to show which ones, they're all shit and you can probably find a debunking of one if you search for the study, author, and a debunk/breakdown), or if he looked at them at all instead of just taking other peoples words for it, but he probably believes there's a benefit to "real" trans people when they get gender-affirming care. Recent studies have shown that trans people are
MORE suicidal
after medically transitioning, and even
old anecdotes show that trans people killing themselves after transitioning is an age-old tradition. So transitioning doesn't even help them.
"You're assuming that trans people are simply misinterpreting their preferences rather than experiencing a fundamental disconnect between their gender identity and assigned sex.
They are, literally, misinterpreting their preferences. Trans people are
3-6 times more likely to be autistic, which on it's own is enough to justify social confusion, and especially social identity confusion like "I want long hair and painted nails, am I a girl?". There's also the contagious ideas about how "if you've thought about being trans, you're probably trans" and "you don't need a reason to transition" and that "gender-affirming care should be freely available and not gatekept because
gender self-determination is a human right and key part of autonomy" (paraphrasing because I can't be assed to read that shit again). The difference between a man who wears makeup and a trans-identified man who wears makeup is just a lot of useless inward self-centered rumination and the declaration of "I am a woman". And if he says "
maybe I'm a woman"? Then he's nonbinary.
I kept trying to tell him that the whole sex and gender being different was something a lot of trans people online don't believe in anymore and that they really think they're biological women/female . It's even something that can get you banned from reddit but he just laughed it off and accused me of using outliers to generalize an entire community.
Even if the people insisting that troons were biologically female
were outliers, at least a handful of those outliers are very prominent, which drastically changes things. The majority of people will believe something if it's from someone they trust, if it sounds smart enough, or if it aligns with their own personal beliefs and/or the beliefs of their herd. See how one sports-winning tranny, Veronica Ivy,
goes on a tv show and shits out "I am a biological female because I'm biological and I identify as female". Then someone like Erin Reed, who is both a prominent transgender activist journalist and married to an elected transgender US state representative, says it too (with slightly smarter, but still incorrect reasoning):
while various activist groups (and
doctors!) claim that there's not any difference between male and female. Eventually it all trickles down until the rest of the group is fully saturated with this rhetorical fat. This is from the
recent controversy about the spa that had a
single monthly "cultural and religious" female-only night, for women who couldn't be naked in front of males:
This might end up getting tangly, but ask him to define exactly what a "gender identity" is, what it actually is if it's both separate from sex and also not sexist stereotypes, while also somehow being tangentially connected to ever-changing
still sexist modern sex stereotypes, and how it meshes with other things trans people crow about like "gender isn't real, so you can do what you want" and "gender-nonconforming trans people" like feminine trans boys or butch trans women. Maybe make him go through the
gender dysphoria bible or other "am I trans?" guides made by trans people, and then ask him if he would qualify as a woman/nonbinary at the end. It's a bit off-topic to your post, but
Inauthentic Selves is also a read I would recommend to anybody, the "What is transgenderism?" section has a nice breakdown on what medical and activist groups consider valid transition criteria (specifically for children).