We've seen the "Blade" trilogy, "Kick-Ass" and its sequel, and "Punisher: War Zone," but it wasn't really until the record-smashing success of "Deadpool" that the demand for R-rated superheroes movies became so boisterous that studios have agreed to comply.

Fox is gearing "Wolverine 3" toward an R-rating, while Warner Bros. will offer an R-rated DVD release of its PG-13 tent pole "Batman v Superman: Dawn of Justice" and an R-rated animated adaptation of DC Comics' "Batman: The Killing Joke." But when the comic-book source material for these movies is largely suitable for the PG and PG-13 crowd, why are fans so ravenous for more mature adaptations? And when we say we want an R-rated Wolverine movie, what are we really asking for?

Of course, PG-13 rating doesn't mean a movie is only for kids, or that it can't tackle dark content or sophisticated themes. Christopher Nolan's "Dark Knight" trilogy folded in terrorism, broken spines and class warfare, while "Captain America: Civil War" touched upon political themes of personal responsibility versus government oversight. However, there's something movies must omit to appease the Motion Picture Association of America and secure a more family-friendly PG-13 that will boost their box-office haul by millions: blood.

Not violence, mind you, but blood.

Remember that moment in "The Dark Knight" when a guy takes a shotgun blast to the chest? It's undeniably violent, but there's no blood. Later, the Joker kills Gambol, presumably by slicing open his face or throat. Look back at that scene, with its crude cutaway to shocked reactions punctuated by a random screeching sound effect that implies unseen brutality. Now, try to tell me Nolan didn't make a compromise to keep it PG-13.

The MPAA has scads of bizarre and amorphous standards that must be met, and its hypocrisy on these matters is worth an entire essay on its own. (If you're interested, check out the documentary "This Film Is Not Yet Rated.") But one of the group's most obvious boundaries involves blood: You can heap on the violence, flatten cities and rack up high body counts, as long as you don't show anyone bleeding. (Because seeing violence isn't damaging to kids, but seeing the realistic effects of violence is, I guess?)

I'm not suggesting blood makes a movie better; plenty of gory yet inane horror films prove otherwise. I'm saying blood is a visual storytelling tool too often denied superhero movies.

In "Dawn of Justice," Batman asks Superman if he bleeds, not because he's genuinely curious about Kryptonian biology, but because blood means threat, drama -- high stakes! The bloodlessness of family-friendly superhero movies is a symbol of the censorship inflicted upon them. It's not bloodlust that has fans hungry for a hard-R - although imagine Wolverine's claws going full tilt with life-like sprays of the red stuff! -- it's that we want our superhero stories to have access to the creative freedom blood connotes.

Most of us grew up with the stigma that comics were for nerds, and that superheroes were for children. But over the decades, we've seen superhero movies become an industry in themselves, and nerd culture go mainstream. The stigma is gone, allowing comics, superhero stories and us to grow in new ways. So naturally we want to see stories that reflect our experiences and understandings of the world, not only in realistic gore, but also in language. Sure, it's charming when Captain America scolds Iron Man for his saucy tongue, but how satisfying was it when Deadpool hurled F-bombs? Not every hero needs to let loose like the Merc with a Mouth, but doesn't Wolverine feel more authentically badass and devil-may-care when he's spitting curse words along with his snarling signature "bub"?

Yet hard-R violence and F-bombs aren't all we could get! There could be sex: Not a chaste kiss in front of your super-buds like in "Civil War," not just slinky innuendo like in "Batman Returns," and not skipping to the morning after for banter or brooding like in "Iron Man" or "Dawn of Justice," but a sex scene that needn't be side-stepped or cut away from because of an MPAA panel.

Zack Snyder's R-rated "Watchmen" may have had its faults, but props to him for including a sex scene that was not just steamy but also crucial to the character development of Laurie and Dan (and to a lesser degree Laurie and Doctor Manhattan.) And of course Wade and Vanessa's relationship in "Deadpool" was largely established through refreshingly frank sex scenes. Marvel has been teasing us with shirtless super-studs for years now, and there are scads of fan fiction about this very topic, so I know I'm not alone in wanting to see a more nakedly vulnerable side to these men of steel and women of wonder. It's not just about titillation, or shock value, it's about giving us characters that are fully explored, not sanitized for tykes and toys.

We've already seen a long line of kid-friendly superhero flicks. Now it's our turn to get some great stuff without kiddie comprises. We're adults, we bleed, we curse, we screw -- and we love superhero movies. We're not drag-alongs to the latest Marvel or DC must-see by toy-craving kiddos. We deserve movies that speak to us on our terms, delivering greater stakes, bigger risks and some content that might make the MPAA clutch its pearls, but will have us roaring with unadulterated joy.