Margot Robbie's Harley Quinn movie shows how DC could match Marvel on the big screen

If one didn't know Harley Quinn had become one of the most popular characters among young female geeks, then a glance at the Baltimore Comic-Con floor last fall provided plenty of instant evidence. Where Wonder Women and Marcelines had predominated among the fangirl cosplayers, old- and new-school Harleys now popped up as thick as Tribbles.

And that was even before trailers for this August's Suicide Squad helped turn Margot Robbie's Harley into the female antihero of the moment - with Hollywood noting the massive breakout potential here.

Margot Robbie is set for a Harley Quinn spin-off movie after Suicide Squad.

The Hollywood Reporter broke the news this week that Warner Bros. and DC Entertainment are weighing a Harley spinoff film that would feature multiple female heroes and villains from DC's comic pages - with Robbie attached to produce, as well.

According to reports, Robbie herself began delving into DC's female characters and recruited a woman writer to help develop the idea for WB/DC. She's delivered a gift to their door at an opportune time, as a female superhero might help WB/DC stay competitive against Marvel, which, despite its success, has been lagging when it comes to female superheroes.

While DC is making smart moves on the small screen - amassing traction with such CW shows as Flash and The Arrow, which will soon be joined by Supergirl, migrating from CBS - the home of Superman and Batman just can't seem to compete toe to toe against Marvel on the big screen. (Marvel, of course, is choosing to make its own deft smaller-screen moves on Netflix, with series like Daredevil and Jessica Jones.)

Melissa Benoist does a remarkable job in the lead role on Supergirl.

In March, WB/DC bet big on playing catch-up with its cinematic launch pad that is Batman v Superman: Dawn of Justice. Although the film has been modestly solid at the box office, it cratered by its third domestic weekend, falling short of the billion-dollar threshold.

Henry Cavill as Superman, Gal Gadot as Wonder Woman and Ben Affleck as Batman in a scene from Batman v Superman: Dawn of Justice.

By contrast, Marvel's Captain America: Civil War is poised to pass that magic mark in less than two weeks. Marvel's 13 films have grossed more than $10 billion worldwide. Which brings us to a surprising report this week about the world of Tony Stark.

Marvel's Captain America: Civil War has done well at the movie box office.

Director Shane Black, in promoting The Nice Guys, tells Uproxx this week that female characters were cut and converted from Iron Man 3. He dishes that Guy Pearce's villain Killian was written to be a woman (and that the Maya Hansen and Brandt roles were reduced), and that the gender change was ordered up by the suits in New York because "that toy won't sell as well if it's a female."

Black goes on to make clear that Marvel Studios mastermind Kevin Feige had nothing to do with that decision. "That's Marvel corporate," Black tells Uproxx, "but now you don't have that problem anymore" under the reign of CEO Ike Perlmutter. Which leads the reader to conclude that Marvel Studios may no longer be so backward - let alone marketplace-ignorant - when it comes to prominent female characters.

Yet the commercial sexism of Marvel's past could leave a big opening for DC's big-screen future. Because now that comics-culture geekdom is nearly a 50-50 split by gender, according to some surveys, it would follow that well-crafted solo films for strong women characters can't arrive fast enough.

And here is where Marvel could leave an opening for DC to exploit. Marvel is expected to name its director for Captain Marvel within a matter of weeks, but the film is not slated to arrive for three years.

Gal Gadot as Wonder Woman in Batman v Superman: Dawn of Justice. Photo / Warner Bros. Pictures

Between now and then, DC's Wonder Woman - with Gal Gadot's character so successfully introduced in B v S - is scheduled to open almost exactly one year from now. And by the time Suicide Squad opens this summer, DC should fast-track Robbie's proposed spinoff project.

Warner Bros. has been handed an opening; they should seize it like Black Widow going for an assassin's neck. Because if there's one thing WB still does well, even with B v S, it's a big opening.