Yeah, I’m a mutant. Problem with that?

Of the many things I have enjoyed over the course of the “X-Men” franchise, the regular, dead-serious use of the word “mutant” has been my favorite. “Mutant” is the champagne of teen insults, and “X-Men” holds a special place as the paragon of teen misfit angst dramas. To hear Patrick Stewart purr the handle in his velvety tones is especially satisfying; here, finally, is an oppressed minority that doesn’t bother fiddling with politically correct terms when it has bigger things to worry about.

In “X-Men: The Last Stand,” which delivers on all the momentum and pathos of the first two installments, mutants have made significant political strides, even gaining official representation in the form of the blue, furry Dr. Henry McCoy (Kelsey Grammer), who has been named secretary of Mutant Affairs. What they don’t have yet is a cringe-inducing PC name -- but give them time.

Political strides notwithstanding, the anxious standoff between humans and mutants has reached a crisis point, and the slow-building momentum of the last two installments finally reaches escape velocity. The mutants, as ever, are divided between two camps. On the one hand, there are the militant followers of Magneto (Ian McKellen), who see a war between humans and mutants as the inevitable conclusion to their uneasy draw. On the other, the reform-minded followers of Dr. Charles Xavier (Stewart), who believe in working within the system (hence the hairy representative). But they now face a new, tenebrous evil whose potential for harm is cloaked in good intentions. A “cure” has been developed by a pharmaceutical company that can divest the mutants of their special powers. It’s the anti-weirdo vaccine, basically. Welcome to straight camp.

Wouldn’t you know it, the scientist who developed the cure, Dr. Worthington (Michael Murphy), has a mutant son himself. His name is Warren (Ben Foster), and he’s a sulky, effeminate boy whom we first meet while he’s locked in a bathroom trying to saw his own wings off. The boy has the span of an archangel, but dad fails to see the advantages. “Not you too!” has to be one of the last phrases a kid wants to hear coming from Papa’s mouth; right up there with, “Your mother and I have something to tell you” and “We sent your college fund to the reverend.”

Anyway, that’s the issue at large. The issue at home is more personal, stemming from the loss of Dr. Jean Grey (Famke Janssen), the cucumber-cool smarty-pants who sacrificed herself for the good of the team at the end of the last episode -- sorry, film. At Xavier’s Academy for Gifted Youngsters, there are some pretty devastated middle-age-sters skulking around, namely Wolverine (Hugh Jackman), grumpier than ever, and Cyclops (James Marsden), who can’t stop crying. He also can’t get Jean out of his head. Literally. She calls to him incessantly, until he treks back to Alkali Lake and conjures a very dramatic reunion.

But before that happens, “X3” kicks off with an origin story of sorts for Jean. Twenty years earlier, back when they were still palling around, Xavier and Magneto personally recruited the world’s only known Class-5 mutant to their school, like a couple of Duke basketball coaches. Wooing the precocious 10-year-old in her parents’ living room at the end of a suburban cul-de-sac, they watched in amazement as she levitated every car in the neighborhood. Not trusting even someone as brainy and self-possessed as Jean to control her own abilities, Xavier devised a system to keep them under his control. In a rather paternalistic maneuver, he has diverted them to her subconscious, where they remain latent. The Jean we’ve come to know and love, in other words, turns out to be kind of like one of those newfangled stay-at-home moms who wax elegiac about hot meals -- only not quite as regressive. The new Jean, now called “Dark Phoenix,” is a pale, black-eyed libidinous type whose fits of temper tend to result in the instant pulverization of men who try to stop her. Magneto, it turns out, is more of an enlightened type than Xavier. He’d like to see his girl gone wild -- and on his payroll.

It’s been pointed out all over the place that the mutant concept in “X-Men” is particularly applicable to the gay experience, a metaphor that was cleverly pinged and poked in the films directed by Bryan Singer. In the third installment, which benefits substantially from their momentum and built-up pathos, another potentially powerful, feared and oppressed group is added to the list. At first, I worried about Brett Ratner taking over the franchise at such a climactic moment in the series. (I say that as someone who sat through “After the Sunset.”) And my fears were temporarily stoked during an early action sequence in which Storm (Halle Berry, still underused), Wolverine, Cyclops, Rogue (Anna Paquin) and newcomer Kitty Pryde (Ellen Page) duke it out against a monster machine, yelling all the action movie cliches at one another. (The battle turns out to be a simulation, after which the dialogue is free to find its higher level again.) But here, Ratner seems to have found a theme that he can relate to: A terrifying trio of angry, undomesticated women who all but run away with the movie.

Rogue is as moody and tortured as ever, still trying to figure out a way to have a relationship with nonthreatening Bobby/Iceman (Shawn Ashmore) without killing him (her dewy skin has the unfortunate power to leech the life force from anybody it touches), helplessly watching as Bobby gets closer to the fetching young Kitty. Jean has gone flat-out bonkers, a premenstrual demon with an ax to grind. And the mesmerizing, slithery Mystique (Rebecca Romijn), Magneto’s shape-shifting sidekick, learns a hard lesson in shifting political allegiances. With this trio, “X3” enters new-ish territory, diving headfirst into the mythos of the femme fatale. Together, they’re the Furies for the Hollywood age.

Cyclops may weep and Wolverine moon for good-girl Jean Grey, but as Dark Phoenix, Janssen is infinitely more interesting than she was before. She’s a raging id with the power to whip off Wolverine’s belt buckle with a single dirty thought. (Later, she obliterates his pants with her mind.) She also has the power to get into her lovers’ heads and drive them crazy, like a siren or the “hot psycho chick” of legend. Rogue is still swooningly goth and gloomy as the archetypal toxic girlfriend, and Mystique is hilariously vengeful as a woman scorned. No wonder Storm is pouty. In her new, sportier hairstyle, she is given some new responsibilities and whatnot, but she’s still an insipid weathergirl who doesn’t seem to mesh with the group. “Why can’t you see the truth? Why can’t you just let it go?” Storm rails bitterly at Wolverine. “Because you love her.” It’s the cry of frustrated female friends of love-tortured boys everywhere, a cry that’s doomed to fall on deaf ears.

The conflict comes to a head during a standoff at the pharmaceutical lab, cleverly located on Alcatraz Island. Dr. Worthington has repurposed the prison to house his secret weapon: an eerie young mutant named Jimmy, played by the eerie young actor Cameron Bright. Jimmy has the power to neutralize mutants’ superpowers. It’s a tricky gift; the very thing that makes him part of the community is the very thing the community can’t withstand. The battle for Jimmy culminates in an impressive display of powers for Magneto, who turns the Golden Gate Bridge and Alcatraz into unmistakable tourist traps once and for all. The political future of the mutants, however, remains TBD. And that’s a good thing.

*

‘X-Men: The Last Stand’

MPAA rating: PG-13 for intense sequences of action violence, some sexual content and language

A 20th Century Fox release in association with Marvel Entertainment. Director Brett Ratner. Screenplay Simon Kinberg & Zak Penn. Producers Lauren Shuler Donner, Ralph Winter, Avi Arad. Director of photography Dante Spinotti. Editors Mark Helfrich, Mark Goldblatt, Julia Wong. Running time: 1 hour, 44 minutes.

In general release.