Q. I have a daughter who is 7 1/2 years old and has just finished the second grade.

Recently she's received several birthday invitations for "sleep-over" parties. My husband and I feel that she is mature enough but I don't know every family well enough to let her stay overnight. We told her she was too young to go and she has accepted this well.

It seems to me that it's hard enough to plan a party for children for a couple of hours but overnight parties are ridiculous! Is this a new birthday phenomenon?

A. Yes, the sleep-over party is a growing fad for young children and an unfortunate one, because it makes children grow up quicker than nature intended.

For years, slumber parties have been a magical ritual for girls between 11 and 14 -- when they are old enough to stay awake and giggle until 4 or 5 a.m. -- but now they are given for children as young as 6, who often are allowed to stay awake until midnight or 1.

These sleep-overs are daffy, but it's easy to see how they came about.

To give a successful party, parents must remember that children are children, not small adults, and that they have few social graces. Usually a flop or two will get the idea across, but when it doesn't, any new idea seems appealing.

There is also the conformity factor. When the birthday child begs for a sleep-over "because everyone has them" her parents hate to say no. The other parents then let their children go because they don't want them to feel -- or be -- left out.

Still there's no cause for panic.

It isn't the end of the world if your child goes to a very occasional, small, well-chaperoned, early-to-bed sleep-over. The problem comes when the parties are a regular feature of the social calendar. A child under 10 can stay up until 11 or so, but she should only do it very occasionally.

The sleep-over can create emotional, as well as physical, strain. Any child's birthday party is stressful for the guests and the giver and the stress lasts at least as long as the party. A young child doesn't have this kind of stamina.

Neither does her mom. It's hard to do a good job of supervising young children for 15 hours. Adults are needed to assuage bruised feelings, if not bruised knees, and they won't do it very well at 1 in the morning.

Sleep-overs have other drawbacks. They exclude those children who are afraid to spend the night away from home or who still wet the bed or those whose parents, like you, are more protective.

You and other parents can help squash the growing sleep-over trend if you encourage more traditional parties, by the ones you give and those you let your children attend.

The best parties for children only last two to three hours, are much more structured than a sleep-over and center around a theme in which the children take an active part: a treasure hunt, a fortune-telling party, a hat-making party, a swimming party -- anything where the children can be so busy they forget to be shy and where they can overlook their awkwardness.

There is one kind of sleep-over that fits into that slot. An overnight camping trip with parents can be great if limited to two or three children. The outdoors is both calming and invigorating at once and the night and the stars and the cooking by campfire will make it memorable.

It would be tempting to let your daughter follow the crowd to today's popular sleep-over, but as you've already discovered, it isn't mandatory. For now, at least, she accepts your decision, although she'll probably balk in another year or so.

Your ability to say no in the middle years will serve you well when your daughter is a teen-ager and asking for too many privileges too soon.