A new study wants advocates to pay more attention to the “hidden crime” of male rape.

Men who are forced to penetrate their partners are often reluctant to report this abuse, even though they would consider being the victims of rape, and suffer severe emotional trauma because of it, according to a survey published this week by the UK’s Lancaster University Law School, in partnership with Survivors Manchester.

The survey asked male rape victims about the circumstances behind their abuse, and what happened afterward. About 150 men who had experienced “forced penetration” responded to the survey.

Examples of forced-to-penetrate cases included situations like when a man wakes up to find a woman having sex with him without his consent, or being forced to have non-consensual sex with a woman as a result of her blackmailing him. It could also happen as a result of being physically, emotionally or financially threatened by a woman.

Though there weren’t any reliable statistics of how often this happens to the wider population of men, the researchers were more interested in the effect it’s been having on men.

A majority of those men said that it was partners or ex-partners who often repeatedly forced the men to have sex with them — often as part of some kind of domestic abuse. There was also a startling amount of childhood sexual abuse where men were forced to penetrate women.

Most men worried they wouldn’t be believed — that others would wonder how a man could be raped if he was the one penetrating the woman. Feelings of guilt and self-blame were usually the reasons why men didn’t report or tell anyone about the incidents, the study says.

Researchers found that the abuse had long-lasting effects: Men forced to have sex with women were likely to experience significant mental health issues, including depression, anxiety and suicidal thoughts. If often took them years to get help or support from mental health professionals or their support system.

“These new findings have provided a far greater insight and understanding about this ‘hidden crime,’ ” says the study’s leader, Dr. Siobhan Weare. “This is a hugely under-discussed issue.”