Most of them appeal to "basic biology" but biology is anything but basic. Just because you learned about chromosomes in your high school biology course doesn't mean you're actually knowledgeable on the subject. It's much more complex than that. The best argument against this idea, in my opinion, is to bring up intersex people, which there's a huge variety of different conditions and always one that will contradict whatever they believe.

This is all ignoring the fact that none of this matters, so maybe it's best to not be baited into it at all. Gender is not something that needs some precise thing to point at. It's whatever we want it to be.