Bah, bah, bah!" The exaggerated sound my son makes as he jabs another couple of lefts and a right into the heavy bag secured at the side of my house. Jab, right cross, hook. It is always better to exhale when throwing a punch: it helps regulate the breathing and, if you receive a punch, you are less likely to get winded. It can also help accelerate the force of the throw.

Gabriel, with his arms like kindling sticks, is an ebullient seven-year-old who has been training on the bag, learning to skip and move around an imaginary opponent for the past six months. My daughter, Mahoney, who is eight, has been doing it for much the same time, with a little less commitment but the same enthusiasm.

I'm teaching my kids to box. Or, at least, teaching them to keep fit through the most basic aspects of boxing. No punching each other and no actual sparring (unless it's hitting me). I'm not a boxer but I love the sport and have been training on and off for the past few years. Two years ago I set up a heavy bag at the side of my house, a weights bench, a sit-up bench and an area set aside for skipping.

Box. It's a monosyllabic word, but very powerful. It conjures memories of past fights and fighters. It is a civic religion for some. It is the bete noire of sports for others. Either way, it is viewed with the gaze of a voyeur's eye on the folds of a dress. Most nights or mornings I am to be found outside the house, punching away at the bag, skipping to a hypnotic beat on my iPod and shadow-boxing. It has become a mini-obsession, and one I am keen for my children to learn from. I was never overweight but I have lost any excess that might have been gained through the sedentary lifestyle that comes with sitting much of my time behind a desk.

At its most basic level, boxing - indeed, most real athletic endeavour - challenges an individual's physical being. The hardest discipline, of course, is self-discipline and both my son and daughter are now actively asking me to do more with them. They are getting fitter and stronger by the day. Gabriel, when he is a little older, will join a boxing club if he still has the same enthusiasm as he shows now. If he doesn't, he will not be forced to continue. He likes football, but it is with boxing that he shows the greatest desire. Mahoney wants to progress on to gymnastics, having flirted with dancing but finding it boring (she was also an infant ballerina). Now she attends chess classes and Irish dancing; her footwork gets better every time she practises boxing.

According to a recent report, the government is encouraging more secondary schools (in England, at least) to offer boxing to pupils, including girls. A pilot scheme in Sheffield, where 150 pupils are trying their hand at the sport through a partnership between schools and a local amateur club, is already being monitored. With adequate supervision and parental consent, boxing could be funded from the £100m that Gordon Brown made available last year to tackle obesity through more participation in school sport. A body blow for the cotton-wool brigade. I hope schools here in Scotland quickly follow.

Already both my children have displayed a dramatic improvement in their hand-eye co-ordination, and understand the notions of control and discipline. For them, boxing is not about fighting or aggression. It is about fitness and learning to listen and follow rules in a comfortable environment. Too many parents use the excuse that they cannot find the time to exercise themselves, nor to take their kids to football or rugby or tennis or whatever sport they might want to indulge in. Schedules force compromise. Meanwhile, thousands of pounds are spent on gyms that are rarely visited.

A bag, a few pairs of boxing gloves, a set of hand wraps for protection and some sports clothing is all that is required. That and some iron will and discipline. It's disturbing to read (yet again) how unhealthy we are as a nation and the potential effect this will have on our children. A walk down any high street in Scotland (or the UK, for that matter), and it's easy to see the state of our nation's health. We are, frankly, a bunch of disgusting gluttons. Why do we eat so much food? Too many of our children are simply massively overweight.

According to the government, up to 70,000 lives could be saved every year if people improved their diet. One in 10 premature deaths could be avoided if Britons reduced the amount of salt, sugar and fat they eat. My three children have always had a vegetarian (and a smidgen of Rocky Marciano) diet. Although I can still be persuaded by a late- night curry, I have eschewed the fast-food days of the past. Good food (which doesn't mean expensive) and a fair amount of exercise is all that is required. It's not exactly rocket science.

The British Medical Association campaigns vigorously for the banning of boxing and, in light of the number of deaths and serious injuries in the sport, the BMA is always worth listening to. Indeed, the new year could not have got off to a worse start for the boxing advocate following the news of the death in South Korea of Yo Sam Choi, the former WBA light-flyweight champion, following a fight on Christmas Day. Deaths in boxing, as in any sport, are a timely reminder of what athletes risk to entertain the paying masses.

The BMA believes there should be a ban on children below the age of consent from boxing. It believes that injuries caused by boxing include brain damage, acute brain haemorrhage, and ear, eye and nose damage. Only a fool would deny that, at its most elemental, boxing is ferocious. It can also seem anachronistic. Make it safer. But don't ban it. Curiously, I still take the measure of people by their interest, or lack of it, in boxing. With my children, I prefer to encourage the non-contact element, which has obvious physical benefits.

What I hope they are embarking on is a lifelong love of sport, not just boxing. Gabriel has shown a particular talent already. Six months ago, he could not skip and was flummoxed by the very idea of it. Now he skips easily and his breathing technique has improved immensely. Most children take a while to develop decent co-ordination. Gabriel has quickly learned to sway like a cobra. He throws punches in combinations and bounces confidently on his toes. But the boxing training only follows after he has finished his homework; at weekends after he has cleaned his room.

Both children are polite and mannered. Both are strong and agile. They also do many of the things their parents tell them not to - they are normal children. They are not, by any stretch of the imagination, obsessed. They have a Nintendo Wii and a PlayStation, though their time playing games is rationed. The play-paradise of childhood won't last for ever, and they will decide themselves what sports they will or won't take part in. At least they will have a strong platform to do so.

Someone once said that our children are ourselves, only a couple of decades or so younger. I often ask myself if the only reason they are boxing is because it's me who enjoys it. The answer, of course, is yes. And I'm conscious of the dangerous aspect of boxing, and that boxers can and do (and always will) get hurt. A salutary lesson came last August when I broke my thumb on the bag due to a badly wrapped hand and a poorly executed hook. A Bennett fracture is a break at the base of the thumb: it requires surgery and the insertion of a pin. It will be operated on in two weeks' time. But I still believe the benefits outweigh the risks.

Gabriel hits the bag, adjusts his feet, adjusts his focus and then moves in again. I throw a soft glove towards his face and he throws his hands up in defence. Then it is Mahoney's turn. She smiles beatifically. Years ago I interviewed the legendary Scots boxer Ken Buchanan. Asked finally why he fought, he looked straight at me and said: "Son, we're all fighters, every single one of us. Fighting is the first sport of every man and woman. From the minute we're born, we're fighting to breathe, to open our eyes. We're fighting to walk and we're fighting to talk. You can't get rid of the desire to fight when it's your very first lesson in life."