For more than three decades, the walls of the visitors' locker room at the University of Iowa's Kinnick Stadium have been pink. When the football stadium was renovated in 2005, the university took the theme even further, adding new lockers, showers, and urinals all featuring various shades of the color.

While it remains a beloved bit of visual smack-talk for many Hawkeye fans -- and was even featured in a recent ESPN ad about college traditions -- some students and faculty have decried the color scheme as sexist and discriminatory. Today, demonstrators dressed as robots are expected to march on the campus to protest the locker room's enduring paint job.

"I wanted to mix fun and activism by fighting absurdity with absurdity," Kembrew McLeod, an Iowa communications professor and the organizer of the march, wrote in a recent opinion piece.

McLeod has a history of dressing as a robot to raise awareness about social issues, previously donning his costume to heckle the likes of President Clinton and Michelle Bachmann. His newest robotic prank, called the "Million Robot March Against Pink Locker Rooms," will coincide with Fry Fest, an annual celebration of Iowa football and of one-time Iowa football coach Hayden Fry. It was Fry who first had the locker room painted pink in 1979.

"There is no denying that Fry’s tactic is rooted in an antiquated age when homophobic and sexist epithets were the norm in sports," McLeod said.

The protesting robots may amount to little more than a metallic annoyance for the university and football fans, but others critical of the locker room have warned of more serious action.

Since 2005 Jill Gaulding, a former University of Iowa law professor, has threatened to sue or file a federal complaint against the university under Title IX of the Education Amendments of 1972, the law that forbids gender discrimination at colleges. On Thursday, Gaulding, who is now a lawyer with the nonprofit law firm Gender Justice, said the "discussions are still ongoing," and that the locker room's color is a type of gender slur.

"It sends the message that anything associated with female is lesser-than," Gaulding said. "The minute I read about the pink locker room and how the university had built it even pinker, it felt like somebody had just reached out and slapped me across the face. It was that insulting. People know what it means."

Erin Buzuvis, the director of the Center for Gender & Sexuality Studies at Western New England University, said that the locker room is at odds with Title IX, but that a lawsuit could be difficult to win.

"Title IX's application to athletics is aimed at equalizing the treatment of female athletes as well as their opportunities to play," Buzuvis said. "If you accept that using pink in the visitors' locker room operates a symbolic gesture of emasculation towards the team's opponents, the pink locker room certainly represents a form of unequal treatment, since the symbolism trades on pink's association with women and stereotypes about women's inferior athleticism."

In order for a discrimination lawsuit to have any legs, she said, a plaintiff must prove that the university intended to discriminate. And Iowa administrators continue to insist that the color of the locker room is not discriminatory but psychological, and have made clear that the locker room is not going anywhere any time soon.

"The University of Iowa is aware that some people are calling for the visitors’ locker room in Kinnick Stadium to be painted a different color, while others have stated it should retain its current shade," the university said in a statement. "The UI respects the rights of both groups to express their views."

In May, The Daily Iowan, the university's student newspaper, also called for the locker room to be redecorated.

"It’s blatantly obvious that the pink locker room is a rather childish example of a destructive and anachronistic culture," the students wrote. "The underlying assumption of the pink locker room is a belief in sexist norms of male superiority and violent masculinity. Open-and-shut case."

There is some limited research on the emotional effects of a certain shade of pink known as Baker-Miller or Schauss pink. Those researchers believed the hue to have a calming or weakening effect. Alexander Schauss, the researcher for whom the shade is named, once likened it to a tranquilizer that "saps your energy." The color can be found covering the walls of some "drunk tanks" and jail cells, including most famously (and at Schauss's insistence) those at the United States Naval Correctional Facility in Seattle.

The University of Iowa is not the only team that has used pink to intimidate opponents. In the early 1990s, Colorado State University had a pink locker room until the Western Athletic Conference decided that home and away locker rooms must be painted the same color. Opponents of the South Bend Silver Hawks, a minor league baseball team, also take their post-game showers surrounded by the color. In 2012, a family in Bondurant, Iowa, that donated $3 million of their Powerball winnings to help build a local high school's new stadium had a caveat: the visitors' locker room had to be pink.

Fry, the revered Iowa football coach, hinted at a deeper psychological reasoning behind the color in his 1999 memoir, but then undercut that explanation by still associating the color with girls.

"It's a passive color, and we hoped it would put our opponents in a passive mood," he wrote. "Also, pink is often found in girls' bedrooms, and because of that some consider it a sissy color."

At one point, pink was actually more often found in boy's rooms, and conventional wisdom dictated that it was a "boys' color." The June 1918 issue of the children's market trade publication Earnshaw's stated that "the generally accepted rule is pink for the boys, and blue for the girls." That changed around the 1940s, and pink and girls have been closely linked ever since. It's an association, Gaulding said, that leads most fans and players to one interpretation of the locker room's color: pink is for sissies.

Gaulding said she doesn't buy the argument that the pink locker room is based on the science of the color.

"Look at the coverage of the opposing players over the years," she said. "They interview those guys, and they say the color gets them 'fired up' and 'I don't like being disrespected.' What's disrespectful about a calming color? They feel disrespected because everybody acknowledges that this is about gender."