He communicates in monosyllabic grunts, rarely washes, and walks stooped as if the world rests on his shoulders. Despite your best intentions, he strays into temptation - fast cars, alcohol, sex. You wonder where the impish little boy you once knew has gone, and how on earth he's going to turn out to be a good man.
If the world of teenage boys is totally different to the rest of ours, then Celia Lashlie is an invader. She's proudly feminist, a former women's prison manager, and yet she's been delving into the heads of teenage boys.
But despite having worked on the project for four years and writing a book on it, she'll protest if you suggest she has been the leader. What she will admit is that it took a woman to see what she has in the Good Man Project, which began in September 2001 when Nelson College headmaster Salvi Gargiulo invited Lashlie to the Heads of Boys' Schools Conference.
The project aimed to discover what it meant to be a good man, and how best to guide boys through adolescence to reach that ideal. To achieve it, Lashlie talked with 180 classes of boys ranging from Years 7 to 13.
The experience left her sure she never wants to stand before another class, but it also gave her an insight into teenage boys, and an appreciation of men.
"I'm saddened by the negating of men that occurs and while I'm very clear that I'm a feminist, I do worry about the ongoing effects of the feminist revolution. One is the perception we've left with girls that they can do everything, and two is that we're in danger of some of our boys automatically assuming they're second-class citizens."
For a feminist warrior, Lashlie seems to be going out of her way to agitate the sisterhood. The book, He'll Be OK - Growing Gorgeous Boys into Good Men, has a controversial message for mothers, one many do not want to hear.
"I've written the book to tell mothers to step back," says Lashlie.
She believes that boys cross the "bridge of adolescence" between Years 9 to 13, and that during that time, mothers need to take a less direct role in their sons' lives - to get off the bridge.
"It's not about mothers abandoning their sons," she writes. "It's about them accepting that for a time they will walk beside the bridge of adolescence rather than on it, or if they can't quite manage to stay off the bridge, that they at least commit to walking on one side."
Mothers need to understand that they do not need to nurture their teenage sons, and nor do their sons want to be nurtured.
"That's the part she will struggle with most," says Lashlie. "For him to get where he needs to go, he needs to have that space where he feels his mother isn't following him around. What he does know with unerring certainty is that, should he have a rough patch, he has only to turn and she's there."
The message has been the cause of strong reaction around the country.
At one meeting a group of mothers voted to refuse to get off the bridge. "I said, 'Okay, I'll build you a clip-on lane, but get off the bloody middle'."
Clear boundaries need to be set, but a boy needs to feel free.
"Unless you let him go, he's not going to be okay. The more you hold on to him at that stage, the more extreme his behaviour is going to have to be to get you to let go."
Doing his ironing, washing, and making his lunch may make mum feel good, but it's not helping the son.
Fathers, meanwhile, should definitely be on the bridge, even if that just means taking five minutes each day to talk to their son, ask how his day was, show an interest.
"The sad thing about dads was that they thought they had to be something different. They don't - they just have to be who they are. They're just dad - it's enough."
For solo mothers, Lashlie says it is important they recognise the need for their sons to have time with men. She is not saying there needs to be a male in the house, just that there should be someone for the boy to be around from time to time.
"Some of them won't have anybody, but most will have a grandfather, uncle, males in the father's family."
Lashlie knows about bringing up children alone. In the early 1980s, her marriage broke up when her son and daughter were barely school age.
Her involvement with the Good Man Project has caused her to look back at her life and realise mistakes she made with her son, now 28. "I've realised that I would have been one of the mothers from hell. I sent him to a single-sex school and then proceeded to tell the school what they weren't doing for my beloved boy."
She recognises now there were male figures on the fringe of her life whom she should have asked to become involved in her son's life. "I could have said to them, 'Could you come and watch him play soccer or rugby, or if you're going hunting or fishing could you take him?"'
While she starred in a career in the prison service, taking jobs in the male-dominated system that no woman had ever achieved, she says there were many times when as a mother of a teenage boy she was struggling.
"That's why the book is called He'll be OK because I just wanted someone to say that. I thought he was, not out of control, but pretty out there. But looking back I realise there was so much more of him that was present than I could see."
Lashlie has done a lot of looking back lately. Two incidents in her career several years ago turned her life upside down. The first came when she fought prison authorities over plans for Christchurch Women's Prison. The encounter left her persona non grata within the Corrections Department. "My soul took a huge battering and I'm not saying I didn't do some of that to myself."
Soon afterwards, she joined the Special Education Service, but found herself in trouble again, after making an off-the-cuff public comment that a blond-haired, blue-eyed boy was destined to be a killer. The boy was fictional, but Lashlie was accused of breaching client confidentiality. After Government intervention, SES was forced to back down and Lashlie was awarded a new contract. But the experience had changed her.
"The first impact of that was quite devastating because suddenly I realised I was on the outer when I'd always seen myself as a loyal public servant for ever. But there's no bitterness on my part because it started my life on a new journey."
Lashlie cut herself loose from the public service, set out on the speaking circuit and has been busy with other schemes, including a youth employment drive in Nelson, and an attempt to help poor communities realise they can deal with their own problems.
But her real passion is women in jail. She has established a programme to help released inmates and act as an advocacy group for women prisoners' rights. It is typical Lashlie, setting herself up to say in a forthright manner exactly what she thinks, and to fight the system. She has no desire to step back into the system and fight from the inside.
"Most engagement with the bureaucracy leaves me with the sense that I'm wrong and I don't need to live with that any more. Now I'm extraordinarily privileged - the more I say what I think, the more people value me for it."
Which is all part of why the Good Man Project, though conceived and supported by state-run schools, was conducted separately from the Government bureaucracy. "They would have told us what the outcomes had to be before we started."
Instead, the project has been drawn from her own intuition. Her conclusions about what needs to be done, she says, are not rocket science or revolution.
"We've come to the mess we're in because our relationships with one another have dropped away and we've become focused on outputs and ticking boxes and in a way what I've found is part of that picture. We need to stop and connect with each other as human beings again."
Celia Lashlie's advice to parents
* Recognise their desire to live in the moment, their inability and/or unwillingness to plan their lives.
* Never underestimate the power of peer pressure or horizontal learning for adolescent boys.
* The central issue is getting mothers off the bridge of adolescence and fathers onto it.
* Boys like clear boundaries. They have to be able to see and/or feel the consequences of doing or not doing something before it becomes real enough to matter and to motivate them.
* He'll Be Ok - Growing Gorgeous Boys into Good Men, HarperCollins, RRP $35.