1) Has anyone actually had a transgender, intersex or genderqueer character (regardless of whether the player was or was not) in their game? How did you approach the concept in your story? Case studies of respectful, dramatically interesting stories are especially welcome.
Intentionally? No. Unintentionally? Devices and effects that change gender have shown up numerous times during my various campaigns; the variety of reactions both by characters and players has been interesting.
First, there's players who are cool with this and players who - well, aren't, and will move mountains to get the original gender restored somehow no matter what the character might think. No problem; means of changing back are usually available somehow, if one looks. But here I know I'd rather have the player step back and look through the character's eyes, and respond as the character would (which might be with the same revulsion, which is fair enough if that's how the character really would see it).
I've had players who I know are cool with it play a character as not cool at all with it, as that's how the character would react based on its established persona - again, this is fine. Example: one character in my current campaign, played by someone* who plays quite well characters of all genders and preferences, went from female to male and - based on her established character - hated every minute of it. The change was permanent (kind of wish-level stuff, long story), but an associate had a reusable cloak of gender change which could "overwrite" the change and make him her again. However, the cloak effect was dispellable and, as the character was a shape-changing Nature Cleric, also wore off on any shape-shift. So, every time Cassandra became Kassandros off he went to visit his chum with the cloak to get changed back to Cassandra. Later, he-she went to considerable length and no small expense to get the original change undone at the quasi-divine level; and so far this seems to have worked.
And I've had players/characters adopt a new gender and run with it; sometimes changing the sexual preference of the character to go along with the change (e.g. straight male becomes straight female), sometimes not (e.g. straight male becomes lesbian female). This choice I leave completely up to the player. There's a retired character in my current game who started out as male, got changed to female partway through her career, and both player and character ran with it - she's still female today. That said, I've no idea what this character's sexual preferences might be as either gender; it never really came up during her run of play. I should ask her player sometime; I still see him in the game I play in.
* - this player's current characters are a lesbian (I think) Dwarf, an androgynous bio-female bisexual Elf, and a straight (I think) female Aphrodite Cleric who happily gives the gifts of the Goddess wherever she goes. Woefully-unlucky Cassandra is now a long-term captive (or worse) of Mind Flayers.
Lan-"yes, this game can and sometimes will be cruel to its characters"-efan