The practice of having established characters come out as gay or lesbian – for want of a better term I call it “ret-queering” – has been around for a while. In general I’m OK with it, when handled correctly, since it can nicely parallel the real-life experience of finding out one of your friends or relatives is gay. My favorite example of this was the character of Willow on Buffy the Vampire Slayer. Although I doubt that the character was originally conceived as a lesbian, the process by which she acknowledged her sexual orientation and began her relationship with her first girlfriend was handled realistically and effectively.
The article below talks about DC Comics plan to have one of its established characters come out as queer – which I don’t feel quite as sanguine. The problem for me is that the medium of comics – unlike movies or TV – offers fairly constant views of its characters’ internal monologues as well as their external action and dialogue. From the early “thought bubbles” to the more recent practice of extended narration, you pretty much know what a comic character is thinking all the time. So when a comic book hero comes out, we pretty much have to believe that questions about sexual orientation have never so much as flitted through their minds, which strikes me as false.
I suppose this could be solved by having the story occur on a parallel earth (Earth-Q, one assumes) or Elseworlds-style alternate history, but in that case the development would not be all that earth-shattering. If we can have Batman as a vampire and Superman as a Communist, an alternate gay version of Aquaman isn’t exactly a landmark.