The Duffer brothers' original notes for Stranger Things confirm season 3's subtle hint that Will could be gay. Like all the best film series and TV shows starring young actors, Stranger Things has grown with its protagonists. That meant season 3 began to explore themes of sexuality, as the kids become old enough to understand the more complex world they now live in. The theme of sexuality was best exemplified by Robin, who officially became Stranger Things' first LGBT character.
But viewers also noticed another line of dialogue in Stranger Things season 3, episode 3, that seemed to imply one of the show's actual stars may secretly be gay. "It's not my fault you don't like girls," Mike snapped at Will in the heat of an argument. It's an ambiguous comment, so much so that even actor Finn Wolfhard told THR he had no idea if it meant anything or not. "I don’t even know if it had to do with Will’s sexuality," he observed. "It’s all up to the Duffers and what they want to do."
The Duffer brothers themselves may have already answered the question - in the Stranger Things series bible, which they shared with networks when they were pitching the show. This version of Stranger Things was very different to the final series; it was actually named Montauk, after the sleepy Long Island town where it was originally set. But the core ideas, and indeed the characters themselves, are very familiar indeed. That makes the series bible's description of Will particularly interesting.
"WILL BYERS, twelve, is a sweet, sensitive kid with sexual identity issues. He only recently came to the realization that he does not fit into 1980s definition of 'normal.' His innocent choices, such as his colorful clothes, prove a constant source of bullying. Like Mike, Will escapes through fantasy gaming, where he can be himself, uninhibited. He has a close relationship with his mother, Joyce. His brother, Jonathan, helps raise him in lieu of their father, who abandoned them four years ago."
For all the changes the Duffer brothers made to Stranger Things during production, this seems to be an accurate description of Noah Schnapp's Will. The series bible stresses Will's use of fantasy as a form of escapism, and indeed that was a major part of his character arc in Stranger Things season 3. Will sensed the Mind Flayer's presence in Hawkins from the moment the Russian Gate began to open, but he initially repressed that knowledge, desperately seeking to escape into the games he and his friends had played together in the past. Many teenage trauma victims regress a few years rather than face a crisis, and that was exactly what happened with Will.
And the Stranger Things bible certainly supports the idea that Will is gay. It stresses his "sexual identity issues," and that Will himself is struggling with the realization that "he does not fit into 1980s definition of 'normal.'" This is a confusing time for any teenager, but in the 1980s homosexuality was the subject of a moral panic, a result of the AIDS epidemic. Will would have good reason to fear how his friends would react if he came out to them; indeed, it's possible this fear has led him to repress his sexuality until now. If that's the case, Mike's thoughtless words could prove pivotal, ultimately forcing Will to confront the truth about himself in Stranger Things season 4.