imho before you get into the politics of whether or not an adopted child can call their teenage parents mommy and daddy, SAO should deal with whether or not an AI is effectively a human being within the constraints of its own systems or not.
I felt like they did SAO's brand of that with the story of why Yui was cut from the game, came back, and then was under target for deletion. It forced a part of the game to be on an equal level with the players, and then gave it the same basic fear of death.
Reminds me of making friends in an MMO; I don't really care about your sex or preferences IRL half the time. The "reality" of the game is all I'm going to think or talk about, because getting into the nitty gritty of things just adds in needless complication.
It basically already said 'yes' by implication, but it'd have been nice to address it. (Of course, SAO addressing anything of its weird shit it brings up by implication would be nice)
This is another thing Log Horizon plays well with, btw. I feel the show is pretty aware of the audiences expectations, and sees no rush to tell you things, letting you work out your own theories. The main cast also nudges you in a direction to support your thoughts, so nothing feels forgotten, simply like it's on the backburner.
By the time you get to see if what you expected is true, you and the cast are both figuring out how to deal with the reality of the situation. Most varieties of viewer should have a character that voices their thoughts within the show, and that, in turn makes it pretty easy to fall for even the side characters.
To me, this is the RIGHT way to use a large cast in a show; they all exist to allow different viewers to experience the tale from personally familiar perspectives. It's not nearly as alienating as watching a show as an adult, with the only feedback being childish rhetoric.