Yeah, everyone is the hero in their own story, so from their perspective, they surely feel like they know things until they meet an actual biologist challenging them.
TERFs invoke half-remembered high-school level biology as if it was mathematical fact. In actual biological reality, nothing is binary or absolute. I don’t need a PhD in computational biology to know that, but if surely helps.
We could maybe give people like her a glimpse into the sheer defiance that nature has against all attempts to fit into tiny categorical boxes.
It’s not just the topics that she doesn’t understand (especially the intersection of gender with endocrinology and neurology), but everything.
If you are a biologist and think you have found a rule that applies to some part of biology, you will feel deeply uncomfortable until the inevitable exceptions start cropping up that tell you that while the theory is still statistically sound, it’s not unnaturally strict and therefore plausible.
Obviously trans people exist and are valid. Thinking otherwise would be ignoring mountains of biological patterns and data that tell us that every binary in biology isn’t actually clean-cut.