Stirner is a theorist who is highly influential on anarchists (and Marxists, actually). He went to some effort to show a whole range of categories are rigid, sharply delineated, coercive social constructs - and that many of these constructs 'own' us by having power over us mentally and otherwise. We can come to own ourselves by recognising these constructs (translated recently as 'spectres') as such and freeing ourselves from them, able to use them as we wish now that they have no power over us.

The gender binary is just one such rigid/fixed social construct, which, once people take the time to really engage and explore, can be unmade for each and every person.

Once that is done, each person will realise that the way that they relate to their own gender, others' genders, and similarly with sexuality, is totally different. No longer fixed and rigid in their ideas about these things, people often rid themselves of being cis, being attracted to just 'one' gender, and explore queerness as an insurrectionary relation.

It's not necessary to read Stirner to come to this conclusion - most queer theory will get you there, as well as most theories that genuinely reject simple essentialisms and binaristic thinking.