LONDON—A generation of domineering South Asian dads are being blamed for exacerbating the epidemic of young sexually frustrated kids in the West skipping town to go and fight for the so-called Islamic State.

After two years spent with dozens of convicted terrorists, repentant Islamists and a former fighter known as the Godfather of British Jihad, an Emmy award-winning documentary maker says there was a common theme running through almost everyone she interviewed: immigrant fathers who couldn’t deal with the more open sexuality of the West, and who took out their own frustration on their children by abusing them and repressing their sexual urges.

“Nine times out of ten, look to the dad and you’re gonna find he did something; beat them,” Deeyah Khan told the Daily Beast. “I would blame the fathers absolutely.”

Khan explores this subject deeply in her new film, Exposure: Jihad which is premiering on ITV in the U.K. Monday.

Herself a child of immigrants from Pakistan and Afghanistan, her film explores a host of other factors that contribute to the radicalization of young men and women. But parents who struggled and failed to adapt to the Western world in which they were raising their children showed up time and again.

Strict fathers, and sometimes mothers, often refuse to accept their sons’ fascination with girls, sports and the rest of the modern world—helping to create a situation where they felt isolated in their own homes just as they did as minorities in wider Western society. None of this forces young people into the arms of the jihadis, of course, but it helps to create an environment where radicalization can flourish.

Hate preachers and online terror recruiters are adept at stepping into the void. “These people end up being surrogate dads. So many of the guys, some of whom didn’t want to be on camera, said the same thing. ‘God, they really cared; they would call to see if you got home OK. My Dad never did that,’ one of the guys said,” Khan explained.

One of the former Islamists featured in the documentary is Alyas Karmani, now an imam in Bradford. He said charismatic radicals sucked him into the world of international jihad. “When someone for the first time starts to understand you, emotionally support you—put that arm around you show compassion and love for you—that’s unbelievably powerful and compelling,” he says in the documentary.

One of the most obvious generational rifts between teenagers and their parents is sex. Young Muslims living in the West are caught in an invidious trap; their parents tell them sex before marriage is haram, forbidden, and they want a say in who they eventually marry. And yet they live in the same sexualized society as their non-Muslim school friends.

“There’s a real sense of hate that you have, that I can’t do that,” Karmani says. “And that’s why I find a greater sense of sexual dysfunction sometimes in Muslim communities.”

“You know, I was talking to my wife this morning, and I said: ‘This is all about sex, everything all comes back to sex,’ And she said, ‘Oh you can’t say that.’ But that’s it. These guys just want girls, that’s all they want.”

Joining ISIS promises to release these young men from parental pressure, minority status and sexual frustration all at the same time. Karmani says misguided teenagers fell for idea that heading for Iraq and Syria would make them cool. “I’m there with my gun, which is more or less just a penis extension, out there,” he says. “Look at me, I’m a mujahid now… I’m powerful now, I’m sexy now, girls are going to look at me, and there’s girls who would wanna become my bride now.”

Another British man, who was attracted to jihadism in the pre-ISIS era, told the documentary-makers that even back in the 1980s there was a seductive power of the jihadi warriors.

Munir Zamir became an acolyte of Abu Muntasir, a British mujahid who went to fight first in Afghanistan, then Pakistan and Burma in the 1980s and ’90s.

“This man was famous. Infamous,” Zamir says. “A 6-foot-7 man who can pick up 10 non-Muslims and toss them over a tank—I had to meet this Abu Muntasir.”

“Dressed in black—all black with a black turban,” he continues. “I’d never seen anyone dressed like that in the U.K. Legendary father of jihad—I was in awe of that look. I thought to myself, this is what the warriors look like.”

Abu Muntasir was at the forefront of the jihadi movement in Britain, introducing foreign speakers including the American cleric Anwar Al-Awlaki to the thousands he helped to radicalize.

“I was in the forefront,” he now says. “Saying: ‘What’s wrong with you? Where’s your spirit? How can you be so lazy?’… sprinkled with, lots of emotive terms and words.”

Breaking down in tears during the filming of the documentary, he said he realized he had been wrong when fighting in Burma and meeting young teenagers who begged him for help to quit the conflict and go to school.

“I’d rather live as slaves and have my kids go to school,” he says, between sobs. “What is this honor? I’m happy to be a coward.”

His influence, his projection of righteous and cool fighters, helped send young men to defend their Muslim brothers in Afghanistan, Bosnia and Chechnya in the 1990s. That early quest for jihad was seen by some as more readily associated with conscientious fighters travelling to take up arms in the Spanish Civil War than it was with terrorists and suicide missions.

But, in the words of Karmani: “These were viruses, you could say, that infected the Muslim community…. We infected a generation with that virus.”

The imagery of brave and righteous jihadis was honed and better disseminated first by al-Qaeda and then the even more extreme ISIS, which upped the production values and took their message into the homes of anyone who was interested via Twitter, Facebook and Instagram.

While the Islamist propaganda has undoubtedly improved, Khan argues that Western society and immigrant families should be doing much more to stop South Asian or Muslim teenagers becoming vulnerable to their videos and social media messages.

“They’re being failed by everybody—their family, their local community and us,” she said. “The fact that somebody is able to sell them death and make death look appealing to them and we’re not able to sell them life… That’s not just their fault that’s also a failure on our part.”

Exposure: Jihad: A British Story is on ITV at 10.40pm Monday.