A nursery in Norway has cancelled its traditional carnival celebration saying it encourages gender stereotypes, with boys dressing up in macho superhero costumes and girls in frilly princess dresses.

Renate Kvivesen, the head of the Vikaasen nursery near Trondheim, told Associated Press on Wednesday that “we don’t think it fits our values to host an event where children feel it’s important to fit into specific gender roles”. The nursery has children up to six years old.

Parents were informed by email that the annual dress-up for carnival, held just before Lent in the Christian calendar, would not be taking place as usual this year after a split decision by the parent-teacher board.

Kvivesen said some parents were disappointed but added “the nature of the celebration has changed in recent years so we felt we needed to look again at the arrangements”.

Norwegians are proud of their record in promoting women’s rights. About 40 % of Norwegian lawmakers are women, including the prime minister and finance minister, while company boardrooms are required to have a female quota of four in every 10. Some remain sensitive about letting gender politics affect the upbringing of their children.

One of those who disagreed with the decision to cancel the dress-up was Sarah Askim, a Swiss-born mother of three boys, the youngest of whom attends the nursery.

“I appreciate that they try to open the kids’ minds,” she said. “I am happy if the girls play with cars and the boys play with kitchen stuff. But I won’t dress my boys later on with a skirt. I believe at one point we have to admit that there is difference between girls and boys.”

The email circulated to parents also expressed concern that the holiday was being commercialised. “Not all children experience this day as something positive,” it said.

Hilde Noest, who had planned to send her 18-month-old daughter to nursery in a piglet costume, said some might think of Norway as “the crazy equality country” but added that the decision would help protect children.

“It’s OK if all of the boys want to be Batman and all of the girls want to be princesses,” she said. “But maybe some of them feel differently and they should not be made to feel left out.”