What have we done to our teenagers by giving them the means to watch extreme pornography? ...the dark smartphone habit no parent wants to contemplate.
Joanna Fortune ponders the question for a moment. "I cannot remember," she says, "the last time I met a teenager who hadn't watched pornography."
The child and family psychotherapist says it was different just 10 years ago. "Even as recently as that, I would have been able to count on the fingers of one hand the number of teens who said they watched pornography.
"What's changed," she adds, "is the access. They're no longer dependent on the computer at home and how restrictive that could be.
"They've all got smartphones and tablets now, and once you give a child a Wi-Fi-enabled device, you have to be aware that there is a huge world of pornography just waiting for them to find. And they're finding it - deliberately or not." And children are finding it difficult to look the other way.
When Fortune started her Dublin-based practice, Solamh, in 2010, smartphones were in their infancy. Now, they're everywhere.
It's become customary for many parents to simply hand their primary school-going children a phone or tablet computer.
"Young children are using pornography as a means of sex education," Fortune says. "They're not internalising that this is a performance, it's not real sex - it's acting. It's not how sex is between people.
"Their brains are not fully developed, yet they're seeing more and more hardcore pornography. They're not able to process it. And it can have far-reaching implications for them."
Psychotherapist Stella O'Malley hopes for a national conversation about pornography.
"It needs to happen," she says, "because our children are viewing the most graphic of content and we can't just look the other way.
"[As a society] we thought we were all so open, but we didn't realise the darkness that was there. This is not just ordinary porn. There's a huge amount of pain and misogyny. Unethical porn is so degrading to women - it's about hurting them."
Much like Joanna Fortune's experience, O'Malley says pornography has only become an all-consuming issue for her teenage clients this decade.
'Appalled by themselves'
"My teenage boy clients are sort of appalled by themselves," she says.
"They've been lured into seeing porn they never intended to see. They probably wanted to see boobs, or maybe a bit of sex, but then they end up watching a rape scene. It's being inflicted on them and they're half turned-on, half revolted.
"Boys are being lured into a weird space about sex and it's sort of happened under the radar for the past few years.
"I'd have girls say to me that if they are with a lad, he will often have expectations that came straight from pornography. There's no, 'Can we have anal sex?' The boys are just whacking it in - there's no lubrication or anything. And these are young girls."
O'Malley believes there is a natural progression to the world of hardcore pornography for young boys.
"They go from video games, to sexualised video games, to regular pornography and then to hardcore, extreme porn. It's a straight line - they're all interconnected."
She believes it is essential that parents have conversations with their children about pornography.
"My children are 11 and nine, and I've locked access for them to certain material," she says. "Parents need to get tough. They need to talk to other parents, too. Limiting access is essential. I'm 44 and my generation wasn't exposed to anything like that as a child."
Belfast-based Marcella Leonard is one of the UK and Ireland's leading experts on teenage perpetrators of serious crime.
She is adamant pornography plays a part. "There's a lot of sexual violence in that world," she says.
"There's a culture of aggression - and you've got more and more of our young people who are struggling to interact with their peers. They're becoming more isolated, spending increasingly longer periods on their phones and when they have unfiltered access to the internet, they can very easily come across violent and distressing content, much of it sexualised.
"The Dark Web has now become available on mobile. Up to recently, you could only get it on your desktop and laptop, but now, with so any children in possessions of phones, this very dark place is accessible to them."
Leonard has noticed that many young sexual offenders have become fixated on pornography.
"If they watch extreme content, they wouldn't have just downloaded it straight away. They would likely have watched pornography for months or years and had a need for more extreme material. A 13-year-old boy shouldn't need any stimulus, so why would they need violence to achieve arousal?"
When she assesses a teenage boy about his criminal behaviour, she looks at multiple factors, but these would include his consumption of pornography.
"What's his life been like up to then? What has he been exposed to? You'd look at his school - has he been the victim of a bully? Has he come from a neglectful home? Has he been exposed to domestic violence? We'd be trying to eliminate the possible reasons. At that point, we'd look at pornography - the quantity and nature of what he has been watching online."
Eileen Finnegan is the clinical director of One in Four, the charity that helps victims of sexual violence. She also works in the rehabilitation of sexual offenders.
"I remember being at a conference in Edinburgh five or six years ago and it was about young people and how they were being sexually educated online. I came back to my office in Dublin and said to my colleagues, 'Oh my God, we have no idea what's coming down the line. It was really scary."
That frightening vista has already arrived, she says.