The stereotype persists, despite being as archaic as a codpiece packed in Spandex. When the pop-culture circus comes to town, the thinking goes, the immature, soft-tissue male emerges from his parents’ basement and treks to the showroom floor, geeking out to collectibles and comic art almost exclusively with members of his same chromosomal tribe.

Now, in 2015, we may not have sufficient data on how many nerds reside on subterranean floors at parental expense, but we do know this: as the geeks have inherited the Earth in more recent years, the gender balance of fandom has shifted markedly. And this year, at the 46th Comic-Con International in San Diego, parity was upon us.

Yes, at this year’s Comic-Con , just about every other of the 125,000-plus attendees was female, and the head count was split nearly 50/50. Why, even in describing how we got here, some industry slang now rings as gender-neutral: mamas, you let your babies grow up to be “fanboys”.

“It happened so fast and so completely and without any doubts,” Heidi MacDonald, editor of the comics-culture website The Beat, says. “All of the research I’ve seen in the last year or so backs up this gender parity for things that are considered ‘nerdy’.

“Even three or four years ago, it was easy to ‘question’ what the female participation in various topics was,” MacDonald continues. “But now, it’s beyond question.”

The most recent research landed shortly before the convention opened in July, released by the online ticketing platform Eventbrite, after more than 2,100 respondents in 48 US states and territories were surveyed. Rob Salkowitz, who developed and analysed the data, says that fans have driven the push for geek-culture parity.

“Last year, the numbers showed we were trending in that direction. This year, it’s clear that we are there,” says Salkowitz, citing his data and surveys from other sources and events. “As a result, we’ve seen more sincere efforts from publishers to broaden the audience, and much stronger responses to concerns raised by fans over inclusiveness.”

Part of killing the stereotype through research is understanding that “nerd culture” is so much more vast, of course, than mainstream superhero comics.

“If a person’s idea of ‘comics’ begins and ends with Marvel and DC, I suppose it can look like a bit of a backwater, despite recent exceptions,” Scott McCloud, the cartoonist and leading comics theorist, tells Comic Riffs. “But comics are so much bigger than that now.

“In the industry and culture as a whole, a revolution is clearly under way,” continues McCloud (author of the cartooning bible Understanding Comics and the new graphic novel The Sculptor), who was a featured guest at this year’s Comic-Con.

MacDonald underscores the degree to which comics beyond mainstream superheroes have altered the playing field.

“The manga boom of the 2000s is absolutely ground zero for where this return to comics being for everyone took place,” says MacDonald, who appeared on multiple Comic-Con panels. “For the first time since the 60s, women had their own thing in comics to be fans of, and the girls who read manga back then have grown up, had kids of their own, and they are totally open to comics.”

Stereotypes destroyed … cosplayers at Comic-Con, where attendees were 50-50 male and female this year Photograph: Daniel Knighton/Getty

And Salkowitz notes how gender parity is not some absolute across all types of geek fandom.

“We polled across multiple fandoms, ranging from comics to gaming to anime to ‘comic- and genre-based media’, and we found gender parity at the top line,” says Salkowitz, who is the author of Comic-Con and the Business of Pop Culture. “That is, our sample was split almost exactly 50/50, compared to last year, when it was 54/46 male.

“But when you start to break it down according to how fans identify themselves, we find that no individual fandom is that even,” continues Salkowitz, who discussed his findings at Comic-Con. “Comics, videogaming, hobby gaming and toy collecting are majority male, usually in the 55-to-60% range. Manga/anime, science fiction/fantasy and media fandom are 60 to 65% female. Because today’s big conventions appeal to fans of everything, audiences coming to shows are pretty much gender-balanced. However, it’s still the case that, say, ‘comics’ fandom tends more toward older guys, whereas manga appeals more to younger women.”

Salkowitz, who teaches in the Digital Media programme at the University of Washington, points out the difference, too, between readership and consumerism.

“One important finding is that gender does not have much effect on the behaviour of fans,” Salkowitz says. “Men and women exhibited interest in the same sorts of things, similar spending patterns and similar attendance levels. If anything, women are slightly more intense in their fandom by certain measures.”

So how did geek culture arrive at gender parity with such seeming rapidity? MacDonald, a longtime writer for Publishers Weekly, points to the rise of online life.

“Obviously, social media made it possible for women to express themselves without gatekeepers telling them what is or isn’t appropriate,” MacDonald says, “and there was also a sea change among young women that it’s OK to be interested in this stuff.”

MacDonald also emphasises that gender parity is not a new threshold, but rather a circling back to an earlier time in American comics.

“This is not so much a radical change as a return,” says MacDonald, a former editor at DC’s Vertigo imprint. “If you look at comics promotions of the 40s, it’s clear they were aimed at boys and girls. Even [infamous comics detractor Fredric] Wertham said that boys and girls read dangerous comics. This idea that girls don’t read comics is purely an invention of the early direct-sales market days of the late 70s to about 2000.”

Turning personal, MacDonald says that throughout her life, she’s known that women and girls liked comics. “I was raised in a household where my grandmother and mother read comics to me,” she says of her New Jersey upbringing. “It was the resistance to this idea that flourished in the 80s and 90s, with men thinking that ‘geek stuff’ like Star Trek and comics were ‘their safe space.’ I think it was this impulse that birthed so many gatekeepers to keep girls away from comics.”

A crucial factor, Salkowitz and MacDonald agree, is that a rising tide not only lifts all boats, but also can alter how they’re docked.

Heroism reclaimed from the boys … Dina M poses as Mystique from X-Men at Comic-Con 2015 Photograph: Zuma/Rex

Part of what changed, MacDonald says, “is the overall acceptance of ‘nerd culture’ to the point where it’s the major part of pop culture. It seems like the parts of the media that aren’t touched by comic-book culture are dwindling into a small ivory tower. Seeing women more involved is no surprise, because the Avengers, for instance, are meant for everyone.”

Amid this shift, though, what will happen to any residual prejudice and lingering misogyny that will surely become more exposed and less tolerated?

“Change creates anxiety. These shifts in fandom – not just around gender, but with the arrival of younger fans who discovered fandom through different channels ... young adult fiction, movies and social media, as opposed to reading comics or playing games at arcades – mean that the conversations and experiences associated with fandom are changing,” Salkowitz says. “Publishers and developers are targeting a bigger audience. A lot of the stuff that used to get by when only guys were involved is suddenly not OK. Not everyone is happy about that.

“That said, there’s a difference between being the old guy telling the kids to get off his lawn, and harassing and stalking women online,” Salkowitz says. “The stuff that’s gone on around Gamergate is so plainly unacceptable, it’s hard to believe it has any defenders. Comics has its problems, to be sure, but the misogynistic behaviour doesn’t seem as systematic, self-righteous and agenda-driven as that.”

Besides, gender parity isn’t necessarily the final destination for this engine of change.

“I’m standing by my prediction from over a decade ago that we’ll have a majority female industry by 2024,” McCloud says.

“But even before that, there are bound to be important transformations from the flood of new voices, new stories and new perspectives that process entails.

“I also think it’s cool,” McCloud continues, “that the phrase ‘gender balance’ – which I used in Reinventing Comics – is looking increasingly outdated, as we’re reminded that gender isn’t the either/or proposition some of us were raised with.”

In the meantime, the future of fandom is all around us.

“I was taking the subway home from the Fourth of July fireworks recently, and a family got on all dressed in red, white and blue for the occasion,” MacDonald recounts. “There was a little girl about four or five [years old], and she was holding a plastic sword and was clearly dressed like some kind of warrior woman. Obviously she has been exposed to that archetype in the media from various sources, but it struck me how young she was and how natural this role was for her.

“It’s not that girls need to be socialised into heroic storytelling – it’s that they have to socialised out of liking it.”

This article appeared in Guardian Weekly, which incorporates material from the Washington Post