I have this pet theory that our culture's whole concept of generations -- which I, and pretty much everyone I know, earnestly believe in -- may at some point seem as quirky and unscientific as horoscopes do now to most people. After all, both generations and astrological signs argue that some critical features of personality and behavior differ based on which timespan you were born in -- the difference is only in the scale of the divisions. (Arguably generations are actually a replacement for horoscopes more fit to our times. After all, in an agricultural society with low geographical mobility, everyone born in springtime really does probably share a common set of experiences which differ from those born in autumn. Now that the planting and the harvest are no longer universal experiences, the only ones we have are global and national news events, so that who got shot when you were in high school -- Kennedy? Reagan? the students at Columbine? -- becomes the delimiter).
Since I do share in the superstition of generations, my immediate reaction to your question is "of course it does". There are lots of things to point to and say "look, this is a difference."
I think there's a certain closing of the gap between "literary" writers and writers of science fiction and fantasy, for instance. In North America, at least, lot of "literary" writers of speculative fiction of Margaret Atwood and Kurt Vonnegut's generation seemed to be dead set against associating themselves with SF, and a lot of SF writers and fans of that era often harbor a resentment against their genre having being called garbage. Some reacted by spurning literary effects and being suspicious of any but a "transparent" style; others, like many writers of the sixties and seventies, wanted to "elevate" the genre -- consider Damon Knight's creations like Clarion and SFWA… the New Wave movements of Orbit, Dangerous Visions and New Worlds… Le Guin writing that SF will only come of age when we can write about Mrs. Brown on a spaceship… the programmatic importation of Modernist techniques and virtues… and so on. I am a product of those efforts -- I grew up reading the New Wave, I went to Clarion West. As far as I can tell, we've already won. SF is now cool in the literary establishment, most of the leading lights of high literary publishing my age or younger are avowed SF fans, books with SF themes win Pulitzers all the time (Kavalier & Clay, Oscar Wao), and in many cases whether an author counts as "literary" or "SF" comes down to who they hang out with more than what they write. Literature professors who scorn SF as garbage are now kind of quaint and middlebrow. So I feel like this battle was won for me before I got here.
This also points to a subtler distinction. After Elizabeth Bear famously blogged that Robert Silverberg was unlikely to read the likes of me, her, and David Moles, I ran into Silverberg at a party at Worldcon and we discussed it. He'd read my story "The House Beyond Your Sky" and liked it, and he enumerated its stylistic moves -- present tense narration by a foregrounded plural narrator, things like that -- and reported that he thought to himself, "if he hasn't read me, I'll eat my hat." And of course he's right: I grew up reading Silverberg, Delany, Tiptree, Le Guin, Russ, Dick, Bester, and their innovations are simply in my toolbox (of course, I've also read who they got it from -- Woolf, Joyce, Faulkner...). But it struck me as interesting that his eye was drawn to the use of technique, and that when he sat down -- spurred by Bear's blog post -- to catch up on the young turks, he was looking for what we had added to the toolbox, for how we had furthered the project of the elevation of SF by means of sophisticated techniques.
There certainly are stylistic innovators in my generation, and I will admit that I like to monkey around with style myself. And you could make an argument that in, for instance, Kelly Link, you see the adoption of postmodernist techniques in the same spirit that the New Wave generation adopted modernist techniques. If you want to talk about what my "generation" has "brought to the party", you could talk about slipstream, infernokrusher, irrealist fiction -- fiction which is deeply playful, not just describing a world using (however sophisticated) techniques, but fiction in which there is actually no world being described, but rather language that does not wholly resolve denotatively... a dance with the reader. You could see that as furthering the project Bob Silverberg's gang was engaged in.
But there's also a sense in which "elevating science fiction" and "stylistic innovation" are both very much Boomer projects -- projects about changing the world, overthrowing the old and ushering in the new. They're modernist projects, in the sense that the hippies were a popularization of the modernist agenda (Breton's and Stein's bohemian cliques of 1920s Paris, now at every suburban mall near you). The postmodernist impulse, I think, is that there is nothing to overthrow and nowhere to get to, there is just stuff to play with; modernism's ascending slope, the new triumphing over the old, is replaced with a flat expanse in which the old and the new are equidistant and fully available, and whether to write in Jane Austen's voice, or Isaac Asimov's, or Virginia Woolf's or Italo Calvino's is always only a tactical, local decision.
There are other things you can point to, like different technologies of interest -- I'll get to that below. There's a different relationship to politics; you see that, to some degree, in the political arguments that erupt in science fiction, such as the recent online discussion of race in SF known as RaceFail '09, which was interesting because it had politically engaged leftists who think of themselves as fighting racism on both sides of it, but for one group (who tended to be older and whiter, though the correlation was not exact) "racist" is a terrible insult you level at your enemies, implying conscious wrongdoing, while for the other, racism is the texture of the world we swim in, and the question for any of us is not "are we racist?" but rather "what bit of racism can I work on undoing next?" Again: Boomers work for a revolution bringing a final change; my generation engages in an ongoing, never-ending work done partly for its own sake.
All that being said -- all those differences you can point to -- I still wonder how much this thing about generations is really a myth, a rubric we impose with some violence on the actual observed data. If you look at it on the level of individual stories and books, does it really hold up? There are stories I write that I like to think I could easily have sold to Orbit, or even to John W. Campbell's Astounding. Does it really make sense to make a divide and put Maureen McHugh's, John Kessel's, Bruce Sterling's recent stories on one side, and Charlie Finlay's, M. Rickert's, and Charlie Stross's stories on another? Are there not Kelly Link stories you could take back in time and publish it as Shirley Jackson's, or Ted Chiang stories you could publish as Ted Sturgeon's? Would Strange Horizons not publish "All Mimsy Were the Borogroves" in a minute, and wouldn't everyone call it slipstream? Do we just enchant ourselves with the myth of generations? (It is, of course, a very postmodern question...)
Well personally, thirty years ago I was nine, and while I was avidly devouring Taran Wanderer and The Dark is Rising then, I think I can safely say I am more passionate now. I wasn't at Worldcon or Wiscon when I was nine, so I don't know how passionate it was, but among the writers I hang out with there is certainly no lack of passion!
I think a lot depends on what you mean by "the genre". There are fewer Hugo voters, but that's probably because SF has become more diffuse. A vastly smaller percentage of people who like to read stories about time travel and robots and vampires and wizards go to -- or have heard of -- Worldcon, than in 1979, not to mention 1959; partly because there are a vastly larger number of such people than there were in 1979 or 1959. And of the people who do go to Worldcon, probably a larger proportion are there today for the filking, or the costumes, or the panels on Buffy.
This is what happens, you know, when the walls of the ghetto fall. More twelve-year-olds are currently reading Twilight than readers of any age have ever read Dune... and even more read Harry Potter. Literary readers no longer blink at something like The Time Traveler's Wife or The Brief and Wondrous Life of Oscar Wao. And that's not even to talk about comics or the movies or TV! We, the people who go to Worldcon, no longer have a lock on the themes or the tropes or the subject matter that we love. I think that's mostly something to celebrate.
As for the quality of the Hugos -- I think voters always voted for their favorite works; the works you're thinking of only became acknowledged masterpieces afterwards. And I think just as many masterpieces are winning today as ever. I think Jonathan Strange and Mr. Norrel is a better book than Dune or The Gods Themselves (never mind Gateway or They'd Rather Be Right). I will put any Ted Chiang or Kelly Link story up against any Heinlein or Niven story from back in the day.
I expect everyone has changed.
Certainly, to return to the topic of what distinguishes "my generation", there are some events and trends of history that are so dramatic that you can ignore them only by the most resolute effort, or by writing ironic retro. One is Moore's Law, and the internet. The dramatic expansion of computing power makes most depictions of robots and computers in classic SF seem silly (and leads to the constant question, "wouldn't they just Google it?"). A corrolary is that a lot of today's SF writers actually worked in the computer industry, rather than in physics or chemistry the way the golden age SF writers did, and thus computers no longer act as a source of handwavy magic. Another unignorable: the dramatic retrenchment of the space program. Another is advances in genetics, medicine, and cybernetics. Putting those together makes the notion of a Star Trek universe -- in which people in plain old human bodies, living plain old human lifespans, using plain old human intelligence, whose computers act just like helpful bodiless human voices, are zipping around the galaxy at faster-than-light speeds -- begin to seem insupportably absurd.
From that you get, in terms of writers today, both people interested in posthumans, extropianism, the Singularity in various flavors, and also -- adding in the general sense of environmental foreboding about the health of our planet -- you get the Mundanes.
And then there are geopolitical changes - the end of the (previous) Cold War, the rise of asymmetrical warfare, the rise of Asia as a commercial power, and at the moment the financial crisis.
We have a tendency always to project whatever's happening now into our futures, so our reactions to these events will be just what make our fiction seem quaint in thirty years. Nonetheless, we should wrestle with them, because it makes our stories alive, in contrast to the only other alternative, which is to not engage with what's going on now, and write based on the stories of the past. It's better to be condemned to being dated eventually, than to being dated even before you start.
Artistically I think SF is going like gangbusters -- and spilling over its boundaries out into the world. I could fill up several pages with recent writers I like: Kelly Link, Ted Chiang, Christopher Barzak, Theodora Goss, Meghan McCarron, Haddayr Copley-Woods, Greg van Eekhout, Hal Duncan, Christopher Rowe, David Moles, M. Rickert, C. C. Finlay, Michael Chabon, Aimee Bender, George Saunders, Jonathan Lethem, Alice Kim, Doug Lain, Margo Lanagan, Paul Park, … (I'm not sure where the borders of "younger generation" are...!)
What an interesting question! I only wish I knew how to answer it in a more sophisticated fashion. I can only say "all of them" -- to say more would require some kind of mental model of "Japanese readers' specifically Japanese reactions to my work", and I am lacking utterly in the tools to build this model -- I think the Japanese readers will have to supply that!
Well, my first collection, The Ant King and Other Stories, just came out last year.
I am now working on a novel set 600,000 years in the future, in a galaxy sparsely populated by declining posthuman civilizations, about a very durable, somewhat depressed, half-a-million year old polymorphic Interpreter in the midst of a revolution, inspired by insurgent paramilitary clowns, on a planet with a trillion people, who have multiple bodies each, two genders which are different than ours (instead of constructing gender, as we do, around "hard" vs. "soft", their genders are "fast" vs. "slow"), and an economy based on pride and birth order. It's influenced by Jared Diamond, Charles Dickens, Alfred Bester, and Samuel Delany, and it's called Resilience.