IN THE movies, they loll about in baby dolls, hair in curlers, paint their toenails and giggle a lot - cos girls just wanna have fun, fun, fun at a Pyjama party. Switch to 1996, and it's a usually called a sleepover. There are no curlers, no frilly nightwear and they get most fun from watching horror videos. But girls will still be girls and, whatever you call it, staying the night in a friend's house is as popular as ever.

Many parents are apprehensive, some downright disapproving. Some of us just don't have enough space. But many of us are happy enough to go along with a pastime that provides the kids with hours of innocent fun - even though it interferes with our sleep.

Boys, of course, as well as girls enjoy spending the night in a mate's house - so sooner or later, most parents have to have a sleepover policy.

There are questions. How old should they be? When is it reasonable to expect a group of, say, 12 year olds, to turn out the light and try to sleep? Should you allow teenage girls to indulge their appetite for scary videos, the scarier the better? Or let boys stay up late watching the loud wham bam thank you Van Damme for waking up the household kind of movie?

They're the kind of questions you'll have plenty of time to ponder on as you stay up late reading, waiting for everyone to settle down and sleep. You've probably been doing this instinctively anyway - but you've certainly been doing it since you listened to horror stories that some parents have to tell.

The story, for example, of the parent on her way home from a night out who met her own young teen wandering around the neighbourhood with friends at 1 a.m. She thought her child was safely tucked up at a sleepover, and so did the host mother, who had gone to bed at midnight. Or several stories where one of the guests arrives at midnight or later, most likely using your sleepover as a cover for an illicit outing.

Whatever age your child is, your basic concerns will be whether you know the family they're staying with well enough to be comfortable about it, and whether there will be adequate supervision. As far as hosting a sleep over yourself goes, you should be extra protective of other people's children.

SLEEPOVERS can, if you allow it, start when children are as young as six or seven and continue through to late teenagerhood, when it is just called "staying the night in someone else's house". Usually it will start out as having one or two friends to stay the night, before escalating into requests for a sleepover party.

Fionnuala Kilfeather, president of the National Parents' Council (Primary) believes that it's okay for six and seven year olds to sleep in friend's house if they really want to and are ready for it - it can help to develop their independence. But of course, you should know the other family well and, if you're the host, be prepared for their over excitement. (These sleepovers should not happen on schoolnights, it goes without saying.)

And take it from a once foolish mother - me - that younger than this is looking for trouble. The memory of having to comfort a distressed five year old visitor who just wanted her mum and dad at 4 a.m. is still vivid over a decade later.

By the time children are 10 and 11, it's quite possible they will be asked to sleepovers where up to 10 children are invited.

Says Kilfeather: "You shouldn't feel under pressure to have such sleepovers yourself, or financially, to spend a lot on them."

At this age it can be more difficult to know who they're visiting, as friends in school can come from neighbourhoods far apart.

"Common sense tells you that you should know where they're going. You could make a point of checking on arrangements by ringing the host family in advance to say `thank you for having my child to stay'. You could also make a point of delivering or collecting your child. And you should also encourage your child to have his or her friends back to your house, to get to know them - it's well worth it," says Kilfeather.

Orla, a Dublin mother of four, believes that it's all important to know the other family - and will say no to an invitation if she is not comfortable about arrangements. "I never went for parties. Usually, the girls didn't ask until they were about 10 or 11, and then I would just let them stay with a friend if I knew that family very well.

"But one of them keeps asking to stay in one house and maybe I'm being unfair, or judging on appearances, or the fact that the mother often leaves someone else in charge, but I'm not happy about the set up, and I say no.

Her concerns go to the heart of what worries many parents, for none of us can be innocent any more about the risk of sexual abuse. Indeed, apparently some English parents have banned sleepovers following an incident in which a child accused a host father of interfering with her. It highlighted the potential risk to children and adults.

Kathleen Kelleher, senior clinical psychologist at the Mater Dei Insitute, Dublin, agrees that some parents won't let, their children out of their sight nowadays. But it's important not to let being protective, get out of hand: she agrees that knowing the host parents, and being confident that a sleepover will be properly supervised and appropriate to the age of the child are the two important factors.

YOU MAY allow your own young teenager to do certain things - watch over 18 videos, go out at night to the local shops with pals, stay alone in the house with perhaps a slightly older brother or sister. But you cannot assume that parents of children you're responsible for at a sleepover would do so, and have no right to make that decision for them, says Fionnuala Kilfeather. So you should check with other parents in advance, even if your own child doesn't like the idea.

As children get older, you need to be extra alert. Most parents worry about the "free house", and you really have to know if an adult will be in a house your child is invited to. Do parents of your guests know where their child is - if the invitation is impromptu, ask them to phone home. Establish ground rules - they must get your permission if they're leaving the house. Watch out for drink and drugs.

As Kathleen Kelleher says, 99 per cent of the time, teenagers aren't codding you. But you'll tempt fate if you're too gullible.

As for how late and how loud, that will probably be decided by your nerves or your neighbours. Sweet dreams.