UPDATE! Thank you for all your questions. Mark will answer as many as he can get to in the video edition of Mark's Mailbox, which will post later today. Please note: Next week's Clubland Q&A will be in a live audio format!

Yesterday's SteynPost was a demographic primer on "The Biggest Issue of Our Time", and it attracted a lot of reaction. Reading the characteristically thoughtful responses from Mark Steyn Club members, it occurred to me it might make a good subject for a new Clubland Q&A. Ever since I started writing about the west's deathbed demography in the years after 9/11, I've encountered a lot of people who object, "Ah, yes, but what about..." - many of which I've answered piecemeal over the last decade, but not previously in one sustained blast. So I thought, for the first of our special-focus Clubland Q&As, we'd take a romp through all the "Yes, but..." topics. If you're a member of The Mark Steyn Club and you've got a question on demography - in Europe, in North America, in China, Africa, the Muslim world - feel free to log in and append it below, and I'll do my best to get to it. For a single-subject Q&A, that's pretty broad and planet-wide, but do try to stay focused on the arithmetic, its consequences, its causes ...and any happy ending you might foresee.

Incidentally, we're still trying to figure out the best format for our Mark Steyn Club question-and-answer sessions. We've done it in print form and in video, and later this month we'll be doing it in audio. More details on that in a few days.

~My children went through a brief "Doctor Who" phase, as I did, also briefly, a zillion doctors earlier. So I was interested to see that the BBC has made the new Doctor a woman, to be played by Jodie Whittaker. In Britain these days, a lot of doctors are women. Or they're Muslim men from Yemen and Somalia with a poor grasp of English - which might have made for an even more exciting glass-ceiling-shattering choice. In The Spectator Brendan O'Neill welcomes the casting of Miss Whittaker, while deploring the attendant ecstasies from the media and Twitter. Along the way he writes about how "obsessed the virtual left is with cultural messaging":

Gone are the old cries for full employment or marches for jobs, and in their place we have an irritating, myopic, often self-serving demand for greater diversity on TV, radio, in magazines. We need a female Doctor, a black James Bond, more female voices on the Today programme, plumper mannequins in shops, traffic lights that are gay-friendly (seriously), in order to make sections of the populace feel less depressed, apparently.

I'm not as relaxed as Mr O'Neill about a Doctor Jodie Whittaker - but then my choice would have been a CGI Patrick Troughton, so what do I know? But I do regard this sort of thing as, to coin a phrase, cultural appropriation - in the sense that what our age mostly does is appropriate the cultural creations of greater talents and make them into something other. The Mighty Thor becomes a woman, Spider-Man turns Afro-Hispanic, Green Lantern goes gay; even in the Archie comics, Archie dies taking a bullet for his gay best friend, and Jughead comes out as asexual.

The clever thing is to create Archie (as Vic Bloom and Bob Montana did in 1941) and Captain America and Iceman, and turning them into modular furniture to be repositioned round the room at will - now female, now gay, now Hispanic - is an achievement of a considerably lesser order. As Brendan O'Neill points out, it's also shallow - although very suited to an age in which Facebook offers you a choice of 50 gender identities. And, unlike real life, at least when sales head south Spider-Man and Green Lantern can transition back entirely painlessly.

But what strikes me in all these feeble pseudo-edgy poseur reboots is how cobwebbed are the superstars of 21st century pop culture: Doctor Who and the X-Men and Avengers date from the Sixties, James Bond from the early Fifties, Captain America and Wonder Woman from the early Forties, Batman and Superman from the Thirties. Why, you'd almost get the impression popular culture was all but tapped out. In that sense, the most radical reboot of all would be to have all these guys played by old white men of the exact age of the characters.

Just to tie it all back to where we came in, obviously massive unprecedented demographic transformation changes not only the future but the past. No one in tomorrow's Britain is going to be much interested in Sherlock Holmes or Hercule Poirot unless the former is a moonlighting imam and the latter a retired inspector with the Brussels mutaween. But the urge to accelerate the process is palpable: it is necessary to instruct the people by making their most beloved characters something other than what they're beloved as. It is thus the old Bolshevik trick of identifying those in the ascendant and those to be diminished. To modify Lenin: Doctor Who, whom?

~The above-mentioned SteynPost and The Mark Steyn Show are made possible through the support of members of The Mark Steyn Club, for which we're very grateful. As I always say, membership of the Club isn't for everyone, but it does ensure that our content - such as my recent interview with Douglas Murray - remains available for everyone, in print, in audio, in video, out there around the world, and maybe once in a while changing a mind or two. For more information on The Mark Steyn Club, see here.

Meanwhile, for existing members, fire away with your demographic questions for our Clubland Q&A...