I have a theory about Sherlock…
MAJOR spoilers for A Scandal in Belgravia under the cut.
Personally I think Cumberbatch plays him that way, so perhaps it took the creators seeing it in action before they figured it out.
Either way, you could also say that if Irene likes women, then Sherlock likes women, too. But I highly doubt that’s what they mean, as Sherlock has shown zero interest in any female on the show. It just wouldn’t make sense, in my opinion.
Another interpretation (from the extended trailer), is that Mycroft is suggesting he’s asexual, too. I think this still works with the gay theory, because it’s not like you can’t be asexual and not have loving, committed relationships. If anything, I love the idea of Sherlock being asexual and finding his emotional partner in John, who balances him out.
(JFC, HOW CAN THIS ONE EPISODE GIVE ME SO MANY FEELINGS? Okay, I’m done now.)
