While Duke Nukem isn't exactly known for a nuanced portrayal of sexuality, Gearbox boss Randy Pitchford revealed that they originally had plans to push their protagonist out of his comfort zone with a gay robot sidekick. Although they dropped the character from Duke Nukem Forever for now, Pitchford says he's reluctant to give too many details lest they bring the character back at some point. He did mention that the plan was for the robot to ultimately sacrifice himself by exploding an internal nuclear generator to stop an alien threat. While the escapist points out this is a pretty common trope in media, everything else Duke Nukem does is rooted in a million other pop culture cliches, so why should this be any different?
While I don't have 100% confidence that this wouldn't have been an embarrassing disaster (see Pitchford's quote defending Duke's misogyny: "We are in the time when most of our heroes have become pussies. They're emo and everyone's trying to take themselves so seriously."), I'm willing to give them the benefit of the doubt. I know there's at least one real life actual gay working on the game, so at least they would have had a point of reference. For now though, we'll just have to either lament what could have been or be glad we dodged a bullet, depending on your perspective.
Duke Nukem had "gay robot" sidekick [Eurogamer]