What's squeezing a woman's bottom got to do with sport?

It could be an image from the hit television series "Mad Men," which documented the ribald world of advertising in 1960s America.

Except this is 2015 and "Who squeezes them in Harelbeke?" is the poster strapline for the elite E3 Harelbeke competition in Belgium, accompanied by that gloved cyclist's hand poised to pinch a woman's bottom.

Unlike the wind provocatively lifting up her skirt, the controversial advertisement wasn't dreamed up out of thin air.

It's inspired by previous winner Slovak Peter Sagan, who pinched a podium girl's behind at the 2013 Tour de Flanders -- something he later apologized for, saying "I promise to act more respectfully in the future."

A week earlier, he was also pictured on the E3 Harelbeke podium, making an ass-grabbing motion towards another flower girl.

E3 Harelbeke's organizers chose to celebrate his antics in their 2015 campaign, sparking a global debate about sexism in cycling that has raced far beyond the billboard.

"Old Boy's Club"

"A guy grabbing a woman's ass is very much indicative of a level of sexual assault," said Kathryn Bertine, former professional cyclist and director of "Half the Road," a documentary about female racers.

"This poster makes cycling look very outdated. They're relying on a 'good old boys club' tactic to help them sell a product -- and in this case that product is racing."

Judging by E3 Harelebeke's provocative standards, the poster could even appear tame compared to previous years.

In 2011 organizers opted for a naked woman lying in a field, while the silhouettes of miniature riders traversed her bare backside. More baffling was last year's poster featuring a woman straddling three other females curled into the shape of a bike.

"Such provocative imagery may have been seen by some in the 1950s and 1960s as a basis for selling products, but marketing communications are a rather more sophisticated and progressive activity than they were 50 years ago," said Simon Chadwick, Professor of Sport Business Strategy and Marketing at Coventry University.

"I think E3 Harelbeke are rather out of kilter with the way that most people think today."

"A playful nod"

Cycling's world governing body, the Union Cycliste Internationale (UCI) has since requested the poster be removed, to which the E3 Harelbeke organisers have agreed -- not that they necessarily see it as offensive themselves.

"Personally, no I don't think it's sexist," Marc Claerhout, E3 Harelebeke manager, told CNN.

Could he see why others might find it offensive?

"I don't know. You have a lot of publicity where you see more than some underwear," he said. "And we didn't mean it as sexist."

The organization has since withdrawn the poster, releasing an official apology to "anyone who might find it intimidating, discriminatory or sexist."

"The organization launched this campaign as a playful nod to the stage incident two years ago in which a rider got ready to squeeze the buttocks of a flower girl," it added.

(CNN)