In its response, Volkswagen Group UK said the ad was about adapting to challenges and that it did not think that a climber, astronaut, or athlete competing in a Paralympic sport were gender stereotypical roles or occupations — although its ad depicted only men in these roles.

The U.K.'s Advertising Standards Authority (ASA) introduced the sexism rules in June after research and a consultation with the ad industry. "Ads that directly contrast male and female stereotypical roles or characteristics need to be handled with care. An ad that depicts a man being adventurous juxtaposed with a woman being delicate or dainty is unlikely to be acceptable," its ruling on the Volkswagen ad stated.

The first, an ad for Volkswagen 's eGolf electric car, showed a man closing a tent on a sheer cliff face, two male astronauts in a space ship and a male athlete with a prosthetic leg doing a long jump, with the text "When we learn to adapt, we can achieve anything." The ad, that was aired in June, finished with the eGolf driving quietly past a woman as she sat on a bench next to a pram, and was banned for showing stereotypes in a way that was likely to cause harm.

Two ads have become the first to be banned for gender stereotyping after new rules came into force in the U.K.

Attendees pass in front of a Mondelez International Inc. booth at the Sweets & Snacks Expo in Chicago, Illinois, U.S., on Tuesday, May 21, 2019

The second, a commercial for Mondelez cream cheese brand Philadelphia, was banned for portraying new fathers for being "somewhat hapless and inattentive." Two men were shown taking their babies to a restaurant where they could choose dishes from a conveyor belt, but both become distracted and accidentally put their children down on it, before one of them says: "Let's not tell mum."

The ASA said that Mondelez broke the rule that ads must not include gender stereotypes that are likely to cause harm, or serious or widespread offence, and that it must not appear again in its current form.

"In combination with the opening scene in which one of the babies was handed over by the mother to the father, and the final scene in which one of the fathers said 'Let's not tell mum,' we considered the ad relied on the stereotype that men were unable to care for children as well as women," the ASA said on its website.

In its response to the ASA, Mondelez UK said it chose two dads to deliberately avoid the stereotype of two new mothers with childcare responsibilities. "There was no intent to stereotype nor did they purposefully make the dads look incompetent or belittle them as they did not fail to look after their children; the dads were simply momentarily distracted by eating Philadelphia," Mondelez stated.

The United Nations campaigning organization the "Unstereotype Alliance" welcomed the ASA's move. "Harmful gender stereotypes have profound consequences. They are behind different forms of discrimination, from limiting women's leadership roles to reducing their economic opportunity. They underlie significant problems of violence against women," its Director of Strategic Partnerships Dan Seymour said in a statement emailed to CNBC on Thursday.

Companies such as Diageo, Procter & Gamble and Mars are members of the alliance, which was launched in 2017 to remove sexism in ads. "Advertisers shape our attitudes on a daily basis. As a result, they have a huge role to play in challenging norms and presenting more progressive and positive role models, and a responsibility to be a force for equality," Seymour added.