Maybe it’s the hair.

Not too long ago, I was watching “Elektra,” the 2005 big-screen superhero adventure starring Jennifer Garner as the title character. During scenes where I was supposed to be admiring her villain-kicking skills, I was instead marveling over the makeup – and the lush mass of hair framing her face even after strenuous activity. It was a shampoo commercial waiting to happen.

Unfortunately, it was also an absurd moment in a ridiculous movie. But it did provide a peek into reasons why there hasn’t been a big, successful, live-action superhero movie with the woman as the lead.

It is a question that has dogged superhero movies for decades without real change – and it’s good time to bring it up again.

This summer, your local cineplex will have not only the just-opened “Iron Man 3” but new looks at Superman and Wolverine. Also, while this year marks the 75th anniversary of Superman, one comics blogger noted that also makes it the 75th anniversary of Lois Lane.

So if, for example, Wolverine can be spun out of X-Men not once but twice (with the second Hugh Jackman movie due in late July), why hasn’t there been a feature starring one of X-Men’s women?

Scarlett Johansson’s Black Widow was more than a little impressive in “Iron Man 2,” returned for “The Avengers” super-gang and is part of the upcoming “Captain America” sequel. But while Iron Man, Thor, the Hulk and Captain America all had their own movies before Avengers, where’s the Black Widow stand-alone feature?

Wonder Woman has been talked about for movie treatment for years, but it may be more years before it actually happens. David Goyer, the screenwriter whose credits include the new “Man of Steel” and Christopher Nolan’s “Dark Knight” trilogy, said in one of Reddit’s Ask Me Anything interviews that “Wonder Woman is a very difficult character to crack.

“More difficult than Superman, who is also more difficult than Batman. Also, a lot of people in Hollywood believe that it’s hard to do a big action movie with a female lead. I happen to disagree with that. But that tends to be the prevailing wisdom.”

And should we be optimistic if those movies actually get made? On those infrequent occasions when women superheroes have taken center stage, the result is as disappointing as “Elektra” or the even worse “Supergirl” (1984).

The latter movie, attempting to match the success of the Christopher Reeve super-flicks, was reviled in its day and looks even worse on re-examination; there’s an early scene where I was riveted by how atrocious a background extra was while just trying to walk through a scene.

Then there’s “My Super Ex-Girlfriend” (2006), whose title alone should tell that it’s not taking superhero-ness seriously.

TV has not been much better. Its “Wonder Woman”? A live-action cartoon, and not in a good way. “The Bionic Woman”? Coolly acted by Lindsay Wagner but, as was often pointed out, somehow less strong than “The Six Million Dollar Man” even though both had bionics.

There have been more effective superhero women in prime-time shows like “Birds of Prey” and “Buffy the Vampire Slayer.” But “Birds” lasted a single season, and Buffy’s powerful-women message takes place in a world that critic Christina Rowley once said is “dominated by patriarchal values.” Another critic, Mary Magoulick, said Buffy and her TV contemporaries Xena and La Femme Nikita “present male fantasies and project the status quo more than they fulfill feminist hopes.”

And that begins to get at the problem facing women superheroes.

In short, they’re working in Boys’ Town.

Men still dominate the studios.

Sue, the one-name-only author of the DC Women Kicking Ass website, spoke for a lot of moviegoers when she lamented a couple of years ago that DC Comics’ announced young-male targeting did more than just ignore its many female readers. It also perpetuated stereotypes with “artwork of female characters that regularly crosses the line from cheesecake to embarrassing,” she said.

Which brings us to the hair. Even if male superheroes have been to varying degrees freshly sliced beefcake, they are still allowed to get mussed up some now and then. Women are expected to be beautiful, well-coiffed and garbed in ways that accentuate their “positives.” So you get tight or revealing costumes, and carefully groomed looks – all of which make any kind of fight scene seem less credible, even silly.

You might expect a strong, central-character, female superhero to dominate men — but that might not sit well with the young men in the audience. (Similarly, angst-ridden young men want to see brooding male characters — but also non-angsty women who are drawn to those men.) “Iron Man 3” pays some tribute to strong women, but the title character is still a man.