Doctor Who doesn't return until this fall, but showrunner Steven Moffat keeps leaking fascinating semi-spoilers about the show and its characters.

Last week, he explained why the Doctor's companions tend to be of the young, pretty female persuasion, and this week he's shedding some light on River Song's sexual preferences. To wit: River is bisexual.

When fans on Twitter asked Moffat what the Doctor would think about gay marriage, Moffat replied, "You'd have to explain gay to him first. Then straight! Then why you were still talking when there's ALL THESE SPACESHIPS!!"

When a Whovian pointed out that the Doctor might have an idea about gay and straight after being with River and meeting Captain Jack Harkness, Moffat responded that both those characters "are happily bi," and that the Doctor "comes from a world where such narrow views seem so ridiculous they're hard to remember."

It's not clear whether River's romantic tastes will play a role in the upcoming season, but it's also good to know that Moffat has given these things some thought as he continues to flesh out Doctor Who's characters.

[bleedingcool.]