For the most part a succinct and thoughtful article. However I do not think it goes far enough. You clearly articulate the idea that “biological sex“ is undisputed by any thinking cis or trans person. That is mostly, but not entirely, correct. If by “biological sex“ you mean primary and secondary sex characteristics, I think we are on the same page. On the other hand if you were including in this the basis of gender identity, I would disagree somewhat. Without getting into the medical specifics, the evidence is quickly accumulating that the brains of trans people, both from a structural and neurochemistry standpoint, more closely resemble those of the genders with which they identify. These are arguably “biological sex” characteristics which are not visible to the naked eye. I think we can agree that it is axiomatic that both cis women and cis men are happy with their bodies because their brains and bodies match. This remains true regardless of sexual preference. It is well settled that being transgender is not a mental illness or deficiency just as being gay or lesbian or nonbinary are not either. The days of believing that we could successfully perform behavioral adjustment or other therapy are thankfully gone for the most part. Where there is no mental illness, there is nothing to cure. For the curious and open minded, knowing that LGBTQ identities cannot be modified by psychotherapeutic methods is a good indicator there must be something else going on. Gender and primary sex characteristics are both as immutable as eye color and I would argue both fall under the broad rubric of “biological sex”. The difference is that one is visible to the naked eye, the other is not. Having a certain visible “biological sex” does not imply the invisible gender portion matches. The immutable characteristics of the brain creating the awareness of gender and primary sex characteristics are not always congruent.

Recognizing this linkage is important, I think, to the debate over the rights of transgendered individuals (women in particular). If the focus is solely on visible sex characteristics, the argument of the GCs and TERFs seems reasonable on the surface. They can argue that believing you are a gender (sex) different than what you look like is merely an eccentricity, whim, fad or mental illness. Too many would agree with them. On the other hand, if they were forced to accept the fact that brain structure and chemistry are fixed, thus gender identity is fixed AND is irrevocably linked to (but not necessarily congruent with) visible sex characteristics, the position becomes a lot harder to defend. It is hard to argue that a “real” woman should not be able to go to the places that women inhabit and do the things that women do. If pressed to choose between whether they knew they were female because they looked like one or because they felt like one, I suspect most women would say it was because they felt female. So which is it? Is a woman her primary sex characteristics or is she defined by her IMMUTABLE self identity? It is a lot harder to argue that she should be excluded from certain places or denied certain rights if the latter is the deciding factor. In my opinion this is crucial to moving the argument off-center from the impasse it seems to find itself in these days. Talking about choice, rights and free will are well and good and seems progressive, but does little to sway the ignorant and indecisive. The evidence of Biology is far more persuasive. Isn’t this what the TERF’s and GC’s have been arguing along? Let’s turn the argument around. As to the bigots, that is a different story…