> These genders have absolutely nothing to do with sexual identity, they're essentially randomly assigned, conferring no additional meaning (but providing a parity check in communication, helping ensure clear transmission).

Sexual identity != gender identity. Gendered pronouns do have a long and interesting history in languages that have them, but that is besides the point. We are talking about an individual who has clearly expressed their gender in a public and visible way, to disregard that to use other pronouns is disrespectful.

> Coming from this history, we shouldn't be too concerned with the way pronouns correspond to individual humans.

Actually we very well should be concerned with pronouns and gender. Individual people have their to define their own identity, including their gender, and to be referred to with the pronouns they identify with. That gendered pronouns have their own history is besides the point, that history is not immutable nor is it the same for different languages and cultures. Indeed, there have been cultures and languages with built in support for many different kinds of gender and gender expression throughout history.

> Second, I don't think it's hard to imagine socially-undesirable consequences of honoring anyone's own claimed gender. I'm thinking of a biological-male claiming to self-identify as female, so that he can use the women's locker room at the gym.

This is a tired argument. Gender identity is a big deal for trans* people, it isn't something that someone just up and decides to do so they can perv out in a locker room.

> So under what circumstances do we want to honor their self-image (or, for that matter, to believe their claimed self-image)?

As a society we generally honor people's personal decisions about their identity. We do so for religious change, name change, adoption, interracial marriage and dating, and so on. Gender is no different, people should be free to express their gender as they see fit.

> Third, with identity politics still having legal bearing in our system, it seems that self-identification of gender may derail efforts to ensure gender equality. Given that there are legal structures in place to protect females, may I (as a biological male) claim to self-identify as female, and achieve those same protections? May I at least self-identify on official forms (thereby making enforcement of workplace protections unenforceable)?

It is really clear you have no background knowledge on the kinds of difficulties trans* people face. Trans* people face discrimination, violence, and employment difficult at high rates. You are trying to make it sound like trans* women aren't women, when they in fact are. Official gender identity on forms is a long standing problem for the trans* community at large. There are many places where you cannot change your officially recognized gender at an institution without jumping through a variety of hoops. There are many places where even attempting to do so will get you verbally abused by a clerk. In many places even existing as visibly trans* invites violence.

> Not that these things are insoluble, but I think that we need to give thought to the repercussions should we choose to take any person's claims of gender at face value.

Gender identity has been written about for decades and there is a huge amount written on the social and legal structure of our society as it relates to gender and gender expression. That you aren't familiar with it is not an excuse to make a bunch off the cuff remarks that, whether you realize it or not, are transphobic. So please, don't try to justify your disrespect of someone who clearly identifies as a woman as Manning does.