andy-1395 on the IMDB boards on the excellent "The History Boys":

But surely this is a science fiction movie

I think everyone has misunderstood the premise of this movie. It's classic science fiction. O.k. I admit, there are no shiny robots, laser guns or faster than light spaceships but it uses that perennial staple of the sci-fi genre, The Alternate Universe.

This movie is set in a boys school that exists in a wonderful gay universe called Alanbennettland. In this marvellous topsy-turvy world, everything is just like our world, except for one teensy little detail. Absolutely everyone and everything in it, is gay. The men are gay, the women are gay, the birds and animals are gay the trees and plants are gay. Everything. All gay. Even....(and this is the really clever bit) The heterosexuals!

Yes this appears to me to be a sci-fi movie. But how to be certain? Let's perform a little reality check shall we.

Well, for one thing, in the universe I'm from, heterosexual teenage boys, certainly ones from from gritty North England industrial towns, don't tend to go around quoting Wittgenstein at each other. They don't tend to spend a lot of time mincing about like girl scouts and cuddling each other every five minutes. In the universe I'm familiar with, heterosexual boys don't tend to spontaneously perform vignettes from romantic 1930's movies.
Heterosexual males, certainly, in my experience don't tend to ask other men to perform fellatio on them.

Also, some heterosexual boys from this universe, may have a bit of a problem with the issue of a sweaty obese old pervert attempting to fondle their testicles constantly. This lot however have no such qualms and cheerfully take in turns to go for bike rides with him.

So yes, I'm forced to conclude that this is a Sci-fi movie pure and simple.

....Hmm, then again maybe it's just an aging poof's personal wank fantasy brought to life on the big screen.