YOU'VE DONE the parties at McDonald's and the Fun Factory, the fancy dress parties, the ones where you hire an entertainer, the bowling parties, the endless pyjama parties. And now they're 16 or 17 or 18.

And they want a Teenage Party.

You've heard about these these are the parties where kids get sick in the vegetable plot, invade the neighbour's garden, break up furniture, rip the radiators from the walls, smash the windows, and climb on the roof to hurl slates to the ground.

Whether the blame falls on gatecrashers or guests, it ends in tears, squad cars at 3 a.m. and sheepish parents mending fences (maybe literally) all over the neighbourhood for weeks afterwards.

Who needs it?

Nobody, says Nick Killian of the National Parents' Council (PostPrimary), who says the consensus amongst parents he knows is that you're just looking for trouble if you host a teenage party.

He puts it more strongly "Avoid them like the plague."

I'm pretty much of this view my self, and yet realise that this might be unfair to those brave parents willing to invite your children to their homes for a celebration of one sort or another. After all, the only other place where teenagers in this age group are likely to get together is a pub or adult disco or nightclub, and for most parents, the only advantage this has (apart from the obvious one that the pub is not your property) is that pubs don't have bedrooms.

However, reasons not to have a teenage party are strong and include damage to your home, alcohol and underage sex under your roof.

We're talking at the moment about parties you've agreed other kind, the party the kids when the parents are away, is stuff of countless teen movies and ads and sitcoms and yes, it certainly does happen here.

Margaret, a mother of three Dublin teenagers, has experienced both kinds of parties. "In the first one, the sanctioned one, we agreed to a boy/girl party for our 17 year old, and went off to the cinema. And we had said absolutely no drink. By the time we got back, at only 11 p.m., there were kids getting sick in the garden."

The next, unsanctioned, party would have put lesser parents off teen parties for life "We went away for a few days leaving the older children, aged 18 and 19, by themselves. The party started innocently enough as just having a few people around. But there were gatecrashers, and people causing trouble and squad cars in the early hours.

"We didn't find out about it until a few days after we got back. There was no serious damage to the house. But when we went around to apologise to all the neighbours, we discovered that many of them had similar experiences. One told us the dead giveaway is coming home to a house that smells of furniture polish."

Margaret and her husband say they won't ban future parties, but advise if you agree to one, stay in the house, upstairs, suffering the noise. Be there so your kids have someone to turn to if things do start getting out of hand. She has found that they will call for help if it's needed.

ANN HAS CONCLUDED something similar after holding an 18th birthday party for her daughter last year. She had allowed parties before, without any trouble, but this one got out of hand again because of gatecrashers. What's her advice?

"Put away everything of value that might get broken, go out, come home at midnight and freak out." But seriously, this year she will allow another party but plans to ask a couple of trusted (and probably biggish) male friends to act as bouncers "If they're not us or friends of the children they won't get emotionally involved and will be able to act dispassionately in dealing with trouble."

Ann wouldn't have a party for 16 and 17 year olds, on the basis that it is impossible to enforce any ban on drink (or, equally worryingly, drugs). But she agrees that there is an element of risk in having a party for the 18 to 21 year old group too, and feels lucky that her one bad experience didn't result in serious structural damage to her home.

But why take the risk of another? "Well, I do trust the kids, and I'd sooner have a party at home where I at least know what's going on."

Nick Killian says that for celebrations like 18th birthday parties, a lot of parents will organise a party in a pub, rather than having it in the house "as the lesser of two evils". Even without drink, he observes, a lot of lads together can cause damage to a house.

Everyone agrees that it would be naive to hold a party for 16 or 17 year olds and expect to ban drink successfully the truth is that kids will drink in the garden, or smuggle it into the house. Faced with this, a lot of us would sooner avoid providing the occasion for underage drinking.

"Some parents end up getting a bad reputation quite innocently,". Killian comments.

As for the unsanctioned party, remember it can happen very easily. Nick Killian confirms that Margaret's experience is not uncommon. You go away for a few days leaving your mature college students holding the fort, they invite a few friends around, everyone in their local hears about it and well, the rest isn't silence.

It would make you long for the days when the worst that could happen was Coke on the carpet, ice cream on the wall and toddlers squabbling over pass the parcel.