All parents want to know what their children are up to. But when doesthat become an invasion of privacy, asks Miriam Donohoe

Pass my flak jacket, please. The war has begun. It seems only a few short years since I said goodbye to the terrible twos. But the battle lines have been drawn again as I launch into the terrible teens and enter combat with my 14-year-old son over what he claims is his right to privacy.

I always swore I would be a cool, hip, no-nag mother. A model mum with an honest and open relationship with my son. A mother he would be proud to bring his mates home to. Sadly, all those rose-tinted dreams of mother-son heaven have been thrown out of the window these past six months. I have become "super nag", a monster daily accused of being a snoop, a nosey parker and a meddler. I have even been called a weapon of mass destruction, the current favoured nickname (grrrrrr). And all I'm doing is trying to keep tabs on my teenager.

Twelve months or so ago we were guaranteed to be told everything. We knew about any problems Stephen was experiencing at school, his successes or defeats on the football or rugby pitch and what his mates were getting up to. I even got a detailed report on his first disco, last June, and the girls he chatted up. He was at his second disco recently - and I wasn't told a thing.

Overnight he has clammed up. He now gives us information only on a need-to-know basis. What he thinks we need to know, by the way.

Like every other teenager in the country, Stephen does most of his communicating via mobile phone and e-mail. We are not the recipients of too many messages from him, just the occasional text wondering if we can pick him up from school, as it's raining, or asking what time we'll be home ourselves (a not-too-subtle ploy aimed at extending his time on the computer to the moment we turn the key in the front door).

The delete button on the computer keyboard is a great weapon in his armory. So is the erase function on the mobile phone. It means we are missing whole conversations he has with people, and all we get is an innocent shaking of the head when we ask if there's stuff he is not being forthcoming about.

I accept the Internet is a fantastic learning resource and source of entertainment for children. But what about the real dangers for children online? Aren't parents constantly warned to watch out for Internet predators? Look at the shocking case last week of the US marine who wooed a 12-year-old British girl over the Internet and convinced her to run away from home.

The problem is that most teenagers go online at home, right after school, when we and other working parents are not at home.

It all came to a head recently when I asked Stephen for his e-mail password. With all this talk about Internet predators I wanted to be a responsible parent and check on whom he was e-mailing. And who was e-mailing him. No threat under the sun could prise the magic password from him. He was entitled to his privacy, he insisted.

And when I picked up his mobile phone the other week and started to casually check his messages, he grabbed it from me, switched it off and refused to give me the PIN. He pulled the privacy line again.

I trust and have every confidence in our eldest child, of course. I couldn't possibly believe anything untoward goes on in these electronic communications channels. But where do I draw the line between wanting to protect, help and educate on the one hand and wanting to respect his desire for privacy and independence on the other? God knows we are entitled to know what our son, at 14 years of age, is up to, who he is mixing with and where he is going. But we aren't into this business of snooping either.

His idea of snooping can often amount to just a polite inquiry on our part about his activities. There are moments when he does open up and when the pre-terrible teen lad emerges once again. And during these moments he gushes forth with his innermost views on everything from his hopes to capital punishment, George Bush and the war in Iraq. We get the full version of "I'm a teenager with attitude".

We just want to reserve the right to ask questions about important issues such as sex, drink and drugs as he heads towards young adulthood. We are reassured by friends who have been here that this obstinacy is part of the growing process. These same friends have emerged from the terrible teens with their children intact. All their warnings about what lay ahead have not prepared us, however, for the testosterone and hormonal force about our house.

I am convinced there must be a middle ground, somewhere that allows me peace of mind and allows him the space, privacy and independence he craves. No doubt I will eventually find it and the rows about what's his, what's ours and what's allowed will become less frequent. In the meantime the battle rages. And the book title is already in my head: How I Survived His Teenage Years, by a hassled mother.

Miriam Donohoe is deputy news editor of The Irish Times