I can't believe this thread is still going, but as stated it was all for fun. Yes, it's for the fans and no... no character is officially gay until stated. It's okay to theorize though. That's what we do when a new game is announced, we talk about the potential plot. So why not have a little fun talking about a character's sexuality? If it makes you uncomfortable then just don't look at the thread? I'm not here to fight- nor do I mean to come off as harsh.
Actually which character is more than likely a virgin is obvious isn't it? Totally Leon because he's been chasing Ada for how long now?
Also kidding, but that's actually fun to think about too. In the realm of sexuality I'd think a lot of these characters are somewhat asexual, but that's only because we've seen them fighting bioterrorism. No time for flirting when there's zombies all around!