Sorry for the delay. I will touch on this point. Judith butler does deny biological sex. "First, the idea that sex is a social construct, for Butler, boils down to the view that our sexed bodies are also performative and, so, they have “no ontological status apart from the various acts which constitute [their] reality” (1999, 173). "

ONTOLOGICAL: relating to or based upon being or existence.

Put the meaning of ontological together with the idea that biological sex is a mere performance that, if taken away, would not exist, and you come to the conclusion that Butler believes sex is not real. To further emphasize my point, here is more from her work:

For Butler, sexed bodies never exist outside social meanings and how we understand gender shapes how we understand sex (1999, 139). Sexed bodies are not empty matter on which gender is constructed, and sex categories are not picked out on the basis of objective features of the world.

What does the above mean, you ask? Well, because Judith doesn't believe in any sort of objective truth relating to humanity, claiming biological sex is a mere social construct is her get-out-of-jail card. She is using a branch of postmodernism feminists which claims all human beings are blank slates, with no inate biological underpinnings.

My last point. Judith butler was born into this world from a woman. What ontological status can explain that? How do animals reproduce? Are they performing their biological sex as well?

Well, thanks for the debate. Since you defeated my other arguments previously, except the Judith biology denial, I humbly concede. Take care!