Predictable retort

phrenology is not real science.

neither are the claims that intersex people don't exist, or that homosexuality is some choice that goes against what nature intends.

my dad makes a lot of these dumb arguments, and then doesn't believe me when i explain that there are disorders which cause people to have a missing sex chromosome, or body parts that don't match their chromosomes, or try to explain how gender dysphoria works and is treated, or even that gender as a social construct is separate from sex as a biological facet. he's not using science to back up these opinions, he's just an old man with dated views and hides behind the "basic biology" rhetoric.

it's funny how the real world consensus among actual scientists and doctors does not conform with conservative politics here.

That's because science is leftist propaganda run by the new world order!!

or something

You don't need gender dysphoria to be trans, that's the argument of yesteryear. People who try to advance that view these days are labelled as 'transmedicalists' and shunned almost as harshly as those who are labelled 'terfs'.

The fashionable view amongst progressives right now is that anyone can claim any gender identity for any reason, and everyone else should be required to validate this. I wonder how you'd attempt to defend this viewpoint to your dad?