Homophobic teasing is the most common “violent behaviour” among teenage boys, a new study has found.

The study, published in the American Journal of Preventive Medicine, looked at whether attitudes towards gender equality affected violence in teenage boys.

It surveyed 866 teenage boys in community settings like after school programmes and libraries, covering 20 lower-resource neighbourhoods in Pittsburgh, Pennsylvania.

According to researchers it is the first study to ask teenage boys about violence and attitudes to gender in “US urban, community-based settings”, rather than schools or clinics.

Researchers found that when male high school students supported equality between genders, they were less likely to engage in violent behaviours, for example bullying or sexual violence.

Boys who had seen their peers engage in at least two different abusive behaviours towards women and girls were twice as likely to commit rape and five times as likely to bully others, regardless of gender.

However, of the 866 teenagers, 73.2 percent had engaged in homophobic teasing, for example calling other “homo” or “gay” in a derogatory way.

The study describes the result as “puzzling”, because in contrast to other violent behaviours, views on gender equality had no effect on levels of homophobic teasing, even though questions assessing their views on equality included some about homophobia.

Alison Culyba, assistant professor of pediatrics in the Division of Adolescent and Young Adult Medicine at UPMC Children’s Hospital of Pittsburgh, told CNN: “It is so commonplace, they may see it as a form of acceptable, possibly even pro-social, interaction with their peers.”

Homophobic, biphobic and transphobic teasing and bullying severely affects teenagers around the world, and can lead to mental health problems and even suicide.

Earlier this year, a study found that 77 percent of LGBT+ teenagers in Ireland had experienced verbal harassment at school, and in Scotland 81 percent of school pupils had heard fellow students making homophobic, biphobic or transphobic comments.