I love (don't love) how TRAs claim that a large number of women are indistinguishable from men (including all butch women, all women with PCOS, etc.) and it's therefore unethical to have single sex toilets because "you'll have to ask every single woman entering the toilet to undress!"
Or use examples of gender critical women mistaking a real woman for a transwoman as "proof" that it's impossible to tell them apart. Like the shooting at the YouTube head office a few years ago - I think people assumed that was a man because, well, most mass shootings are committed by men, and crimes committed by transwomen are falsely attributed to "women" in the press. When photos were released of the perpetrator it became apparent she really was a woman. I remember seeing a big Twitter thread laughing at a GC account who had questioned if the artist Christine McConnell is biologically male, no she's not but the occasional mistake doesn't change the fact that most transwomen are PAINFULLY obvious