The test, on the theme of “love, sex and relationships” was given to pupils aged 13 and 14 in Ostlyckeskolan School in the town of Alingsas on the western coast of Sweden last week. The paper of more than 100 questions was designed for ninth grade pupils.

One of the assignments was to pair different words together. The students were asked how they would a girl who was “sleeping around” (in Swedish, “ligger runt”). The supposedly “correct” answer was given as “a mattress” (in Swedish, “madrass”).

Students took photos of the controversial answer, which soon went viral on the internet.

SKOLPROV. Elever skulle svara på vad "tjej som ligger runt" kallas. Svaret: "Madrass" http://t.co/7cRkShDIaR http://ift.tt/1vccKzj

— Expressen (@Expressen) December 1, 2014

The test prompted an angry reaction both from parents and students.

The situation “is very unfortunate," the school's headteacher, Kerstin Sondefors, told Sweden’s Expressen newspaper, as cited by The Local.

According to Sondefors, the sex test was aimed at informing students more about love and relationships and to explain some words that pupils could encounter in everyday life. Among other words mentioned in the test were “brothel” and “pimp.”

"We must respond to what those students will face in society... I trust that teachers will do this in a good way," she said.

Sondefors added that she had a meeting with parents and explained to them that the school would continue to develop similar themes in future.

Sex education in Sweden has been an obligatory subject since 1956. It is usually first introduced to schoolchildren between the ages of seven and 10.