I don't even have to.
You guys don't even try to deny that you believe gender to be a state of mind.
Your only defense is to try to muddy the waters, and pretend that that's somehow not the same thing as denying science.
Some of you even attack some straw man argument that you invented out of thin air about gays not existing because they don't have babies, or some such. I cannot even remember exactly how it went, because it was so breathtakingly dishonest and stupid.
All that any of that does is prove my point.