LONDON, England – Teachers across England are expected to take lessons on gender bias to the next level by chastising students as young as 5 years old for using “sexist” language in school.

The Institute of Physics, an international organization based in London, issued a series of recommendations for the country’s schools to fight gender stereotypes, and encourage students to study subjects that are more popular for the opposite sex, SchoolsWeek reports.

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The report, titled “Opening Doors: A guide to good practice in countering gender stereotyping in schools,” comes with nine recommendations for school leaders to challenge sexism in schools and in conversations between students as well as in teacher-student interactions.

The initiatives come from feedback at 10 secondary schools in southern England that participated in a pilot project that examined sex bias in the classroom.

“Students were … sensitive to casual comments made by teachers, which, while not consciously sexist, often reinforced gender prejudices,” according to the report, which was funded by the government’s Equalities Office.

“Some schools, mindful of bad behavior from boys, had policies of alternate boy-girl seating, effectively using the girls as buffers to keep the boys apart,” the report notes. “In general, the girls noticed and resented this policy.”

The report goes on to note students were “particularly sensitive” to subtle gender bias from teachers.

“Both girls and boys routinely felt that bad behavior is tolerated more for girls than for boys, whereas for violations of the dress code it was the other way around,” according to the report, which also took issue with teachers who encourage boys to pursue STEM subjects and girls to take on ‘female’ subjects like English and psychology.

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But the more controversial aspect of the report deal with language, and focused on banning ‘sexist’ comments from both teachers and students.

“We have always had clear policies on racist language but now we are making it clear to staff that any kind of sexist language is not acceptable,” Janice Callow, deputy head of one of the pilot schools, Fairfields High School, told the Sunday Times.

“We used to say ‘Man up, cupcake.’ We’ve stopped that,” she said. “Saying ‘Don’t be a girl’ to a boy if they are being a bit wet is also unacceptable. Language is a very powerful tool. You have to be so conscious of what you are saying to children.”

The report also highlighted other types of comments that should no longer be considered appropriate, such as calling boys “sissies,” telling girls to “go make a sandwich,” or calling girls who study “male” subjects “lesbians,” the Telegraph reports.

Eliminating the “sexist” comments from public school discourse is critical to eliminating the gender divide in certain subjects, officials said, which they believe is tied directly to a pay gap that results in women in England earning about 19 cents less per hour than men.

“As a government, we are committed to doing everything we can to help women feel empowered so that no career is seen as off limits,” a government spokesperson told Schools Week.

“That’s why we’re prioritizing work to get more girls into careers into Science, Technology and Engineering subjects – to help bridge a gap in our future economy and get them on the path to some of the highest paid careers.

“While we support the work that IOP has put into this guide and the advice it offers to help get more girls into STEM, we trust schools to know what’s best for their pupils and to adopt the approaches that work for them.”