[Kednicma]

Biological sex has more than two configurations of sex chromosomes possible, in humans. This isn't rocket science, although it is biology.

Also, on your other points: Objective truths can exist, but not all measurements are objective. Not everything is a social construct, but the things that humans believe without empirical evidence are all social constructs.

Postmodernism isn't hard. Y'all're just extremely convinced that reality is locally real, just because you can sense it so vividly, and you're blind to your biases as a result.