I've finally worked out something that's been nagging away at the back of my head for the last year or so. As with many thinks that occupy my attention for any length of time, it's to do with Doctor Who.

Now, when the first Doctor (as portrayed by William Hartnell) appeared on the scene, he was in the company of his granddaughter, Susan. After Susan was left behind in the 22nd century after foiling the Dalek invasion of Earth, many other companions joined him in his travels through time and space. A common reading of the role of the companions is that they stand in for his lost granddaughter; and while all of the companions have not been girls and young women, in all but two instances I can recall the principal companion was young and female (the exceptions are the brief period in which the 4th Doctor travelled alone, and then the period in which he travelled with Adric... but then Adric was pretty feminine, then, wasn't he?).

From the beginning, the Doctor related to the companion as a grandfather would to a child, certainly. When the role passed to Patrick Troughton, a younger man than Hartnell, the Doctor seemed a more avuncular figure, more uncle than grandfather, but still an older relation.

As the years passed, and Doctors came and went, the actors playing the role trended younger and younger, but still the Time Lord remained an avuncular figure in the company of young female companions. But there was never the slightest hint of anything... sexual.... about the relationship.

With the arrival of the 8th Doctor in the Fox made-for-tv movie, everything almost jumped the rails. Paul McGann and Daphne Ashbrook (who played brief companion Dr. Grace Halloway) were close contemporaries in age, though their characters were still separated by a gulf of centuries, and the uncle-companion code broke down. Instead, this was a man and a woman, and things went so far afield that the Doctor actually kissed his companion. Yikes!

Who fandom, I understand, didn't like that so much. So it was probably just as well that there were no further televised adventures of that particular Doctor-Companion arrangement. Things could have gotten much ickier from there.

For the better part of a decade, the Who franchise lay a-moldering in the grave, and then the Russell T. Davies-helmed series featuring the 9th Doctor and his companion Rose. Christopher Eccleston is quite a bit older than Billy Piper, so the old Uncle-Companion structure could have worked, but it never quite seemed to fit. There was something else going on here, and I couldn't quite put my finger on it. It wasn't a romantic relationship, by any means, still purely platonic, but in interviews Davies and the other writers talk quite openly about the characters being "in love." So if the Doctor isn't Rose's grandfather, or uncle, or lover, what is he?

This year, David Tennant took over the role, Doctor number ten, and he's had more than half a series worth of adventures with Rose. Their relationship is similar to that of Rose's with the 9th Doctor, but not quite the same. And still it doesn't seem to fit any of the traditional models.

Last night, we watched the seventh episode of Doctor Who Confidential, the ongoing documentary series that accompanies the new Doctor Who. Mark Gatiss, who narrates the documentary series and who is the writer of this week's episode, "The Idiot's Lantern," was featured, along with commentary from series-helmer Davies. In speaking about the Doctor and Rose, Gatiss and Davies, who are both openly gay, each mentioned something about how much fun the characters were having on their adventures. Davies, in touching on this point, described the two as "best friends."

And then I twigged just what the Doctor and Rose were to one another. The Doctor is a gay man, and Rose is his best friend, a heterosexual woman. I mean this metaphorically, of course, as I don't think the Doctor is actually sexual in the least, but where the previous Doctors have been "uncle" or "grandfather," figuratively and not literally, the 9th and 10th Doctors have been "gay man/best friend."

So much of the relationship makes sense to me, now. Of course they love each other, but in very different ways. Rose loves the Doctor, and if she had her way would have him as a lover, but she knows that isn't possible, and is happy to have him as a friend however she can. And the Doctor, who can't possibly have any sexual interest in Rose, is closer to her than to any other living person, and loves her more than he loves anyone or anything else.

This sheds interesting light on the role of Captain Jack--openly bisexual--and of Mickey--Rose's straight ex-boyfriend--in the series, each of them standing between the two, complicating the politics of the relationship. I'll have to think about that a bit further.

I'm not sure that this is something that Davies intended, when he developed the characters, and whether--assuming that this is a legitimate read and not a question of fannish over-analyzing--this was unconscious.