One of the predicted outcomes of the Singularity is the removal of sex as a characteristic. Note that race would be removed as well. A posthuman (of whatever form) would be free of both sex and race.
Oh boy, I will maybe get flagkilled, but you are wrong: race, sex, clothing, and just about anything easily observable is used by humans to precondition the Bayesian probability of the outcome of any social interaction. I see no reason to expect that AI will be any different in this matter, perhaps only more efficient.
I'm a cyborg platypus, nice catch. Just two chromosomes is not enough to express all the variations of an algorithmic gender. And by the way, we also sometimes have Z's (but that's considered a racial thing, so no asking).
It's hard to predict what beings more intelligent than us will do. Yes sex and race cease to become very valuable concepts when people can configure their bodies to be whatever they like in any mix at any time. But we can also consider that having machine-memory allows us to be very specific with the characteristics we want to advertise. e.g. from one of my favorite sci-fi books The Golden Age, the main character's full name is "Phaethon Prime Rhadamanth Humodified (augment) Uncomposed, Indepconsciousness, Base Neuroformed, Silver-Gray Manorial Schola, Era 7043". We won't lose labels, and objective superiority in certain areas won't go away. (A singular human-sized machine can't hope to compete intellectually with a Jupiter Brain. A machine made of bark will be physically weaker than a machine made of diamond.) But the negative associations could go away, which would largely end racism/sexism, the thing we really care about.
And for that matter, bodiless posthumans could still chose to exhibit whichever characteristics they please. I'd wager that most people on second life, given the freedom to portray themselves however they wish, choose to portray themselves as humanoid with apparent gender.