) Female Marine recruits stand in line before getting lunch in the chow hall during boot camp on February 26, 2013 at MCRD Parris Island, South Carolina. Female enlisted Marines have gone through recruit training at the base since 1949. About 11 percent of female recruits who arrive at the boot camp fail to complete the training, which can be physically and mentally demanding. On January 24, 2013 Secretary of Defense Leon Panetta rescinded an order, which had been in place since 1994, that restricted women from being attached to ground combat units. (Scott Olson/Getty Images)

It’s official. Men rule at pull-ups.

Most female Marines can’t even do three lousy pull-ups!

So goes the latest salvo in the battle of the sexes — a battle we thought was actually over in our relentlessly gender-neutral modern world, where the taunt “you throw like a girl” may soon be banned on elementary-school playgrounds. (Kidding. Sort of.)

Another front in the war opened recently with news that 55 percent of female Marine recruits in boot camp training this past year could not pass a minimum three pull-up requirement. This forced a delay in the planned Jan. 1 implementation of a new physical fitness test mandated a year ago by Gen. James F. Amos, the Marine Corps commandant.

The test made female Marines perform pull-ups rather than giving them the “flexed arm hang” option that allowed a woman to qualify by holding her chin above the bar for at least 15 seconds (a.k.a “the girl pull-up”). Hanging in the balance, so to speak, is the question of whether women in any service are strong enough to be in combat.

Cpl. Tiffanie Chan does her pull ups during morning PT, December 06, 2012, at Camp Lejeune Marine Base, Jacksonville, N.C. The commandant of the Marine Corps has signed off on a change to female Marinesí physical fitness requirements. The change, signed November 27, 2012 and released in a Marine Administrative Message, requires female Marines to perform pull-ups during their physical fitness test (PFT), as opposed to the flexed arm hangs they have been doing since 1975. (Chuck Beckley/AP)

But that is not our concern here. We want to know: Are women actually different from men? Why? How long has this been going on?!

Or, less cosmically, why did so many female Marines struggle with pull-ups?

Several reasons, fitness experts believe. A big factor is superior male upper-body strength, but genetic differences, training approaches, social biases and even concepts of physical beauty play in.

Women generally are not adept at pull-ups, trainers agree, but it’s a myth that women can’t accomplish many pull-ups. Even if they despise doing them.

“When I add them to my all-female classes, everyone hates them with a passion,” says Jay Morgan, 29, a D.C. fitness trainer. “The pull-up takes so much out of them; they always scream, they are p----- off.”

But, he says, “I have clients who couldn’t do one and can now pump out six, seven, eight.”

Eight pull-ups, by the way, is the top score in the temporarily scrubbed female Marine fitness category; for men it’s 20 pull-ups.

“You can train anyone to do a pull up,” says Lisa Reed, 41, an Arlington personal trainer who notes on her Web site that she won a childhood pull-up contest (she did about 15 or 20). “You need time. You have to practice it.”

“It will be harder for us to do the pull-up than the male,” she acknowledges. “Women are always stronger in lower body.”

Men have an unfair advantage in the pull-up quest: Testosterone. It provides more lean muscle mass. Women tend to carry more body fat.

When it comes to pull ups, strong back muscles and abs are important. But other upper body muscles help: the “beach muscles” — biceps, triceps and pectorals — says Morgan. Men who exercise tend to work those muscles the most. Because of the beach thing.

With women, it’s the opposite. They generally eschew strenuous chest, arm and back exercises to avoid, in technical terms, looking like a dude.

“Women are more inclined to work on their lower bodies because that is where their body fat tends to pool at,” Morgan says.

To a certain extent, then, this female quest for physical beauty — designed to attract mates, according to several thousand years of research — has disadvantaged women who want to become the pull-up equals of men. But again, these wider psycho-sexual human anthropological questions are not our concern.

It should be noted, however, that society has long treated women differently when it comes to pull-ups. High-school gym teachers, for example, gave girls the flexed arm hang option, reinforcing the notion that females can’t do pull-ups. Boys, however, had to do pull-ups and even shimmy up ropes. (And that hurt your hands!)

“In my personal opinion, one of the worst things we ever developed in physical fitness classes [was] the ‘girl pullup’ or flexed arm hang,” writes Stew Smith, a former Navy SEAL and fitness expert, on Military.com. “At an early age, we have been telling young girls that they cannot do regular pull-ups because they will never be as strong as boys.

“Well, part of that statement is true,” he adds. “The strongest woman will NEVER be stronger than the strongest man, but I have seen 40-50-year-old mothers of three do 10 pull-ups.”

The Marine Corps instituted its first physical training test for women in 1969. In 1975, that test changed and included the flexed arm hang, according to Capt. Maureen Krebs, a Marine Corps spokeswoman. She said she did not know specifically why that exercise was added.

The 2013 female pull-up phase-in was to include progressive workout plans with exercises to enhance overall upper body strength. But interim data showed it wasn’t working out very well; hence the delay.

The Marines did not want to risk losing recruits and officer candidates because of pull-up failures: “The Commandant [Amos] has no intent to introduce a standard that would negatively affect the current status of female Marines or their ability to continue serving in the Marine Corps,” Krebs said in an e-mail.

For at least the next year, female Marines will have an option of doing the flexed arm hang or pull-ups on the physical training test. But it’s unclear whether a pull-up only test will finally be implemented in 2015.

The lesson in all of this? We surely cannot begin to say, but here’s a try.

Putting physiology, social policy, behavioral theory and military doctrine aside, it appears that for reasons known only to the Maker (in whatever form you may visualize Him or Her), men and women are different.