The annual San Diego Comic-Con is a calendar event for the film industry and showcases the upcoming works of the major studios.

It showcases new trailers, announces new films, hosts panels with actors, directors, writers and artists from film, television and comic-books and is often dominates the news-cycle for entertainment news outlets like us for many days.

This year, however, saw a few surprising points in terms of subject matter and future projects. Warner Bros. and its DC Comics Cinematic Universe debuted the first trailer for Wonder Woman whilst Disney and Marvel Studios confirmed Oscar-winner Brie Larson as Captain Marvel and a release date for the film.

While you might think that they're both not exactly huge points of news, they do represent something that's been missing from modern comic-book movies since their inception - namely, they're both led by women. That's something that comic-book movies have only just now began to catch up with.

Let's take Wonder Woman. Originally debuted in 1941 and created by William Marston and Harry G. Peter, the character has become one of the most recognisable comic-book heroes - male or female - in that time. Aside from Lynda Carter's portrayal of the character in the '70s TV series and the various animated iterations, there hasn't been a live-action version of Wonder Woman on screen since this year's Batman V Superman: Dawn of Justice. An abortive attempt was made in 2011 to return Wonder Woman to the small screen, however the pilot wasn't picked up for series.

In its seventy-year history, Wonder Woman has had only two live-action actors play her. Both Batman and Superman have had eight.

Marvel hasn't fared much better, either.

Since Iron Man launched the modern Marvel era in 2008, there have been thirteen films set in their so-called Cinematic Universe. Aside from the ensemble films like Avengers, Age of Ultron and Guardians of the Galaxy, not one of these films has had a female lead the group. The same goes for Fox's X-Men series or Sony's Spider-Man franchise. In all cases, it's had male superheroes out in front and female superheroes in a supporting role.

Iron Man 2 introduced Black Widow, played by Scarlett Johansson. The character first appeared in 1964, initially as a Russian villain, before eventually defecting to the United States and S.H.I.E.L.D. In 2010, Marvel Studios' chief Kevin Feige confirmed that a Black Widow standalone film was in the works, but so far, nothing concrete has materialised. It's only now with the announcement of Brie Larson and Captain Marvel that it's beginning to catch up. Prior to this, there were only two female-led Marvel creations on-screen and they were both television series - Jessica Jones and Agent Carter, respectively. Like Black Widow and Wonder Woman, Captain Marvel has a long history in comics, beginning all the way back in the '60s.

It may just be that studios are starting to realise that they can't continue to exclude female superheroes indefinitely, as has been the case. With Paul Feig's Ghostbusters, Jennifer Lawrence's Hunger Games and Edge of Tomorrow, studios are beginning to see that audiences are receptive to female-led blockbusters and are beginning to shift stories to cater for that. The question is, of course, why has it taken so long? It surely wasn't for lack of material or, indeed, a lack of desire. There's been countless online petitions for a Wonder Woman film, a Black Widow film and a She-Hulk film and the question is regularly pitched to the likes of Kevin Feige and Geoff Johns at Q&As like the ones held at San Diego Comic-Con.

If comic-book movies and blockbusters are to remain relevant to audiences, they have to start including and representing the other 49% of people on this planet.