I have two daughters -- a 5 1/2-year-old and a 3-year-old.

I realize that sibling rivalry is part of life, but my girls constantly argue and fight when they're together. The older child has been in school on a half-day basis, and that has been the only respite.

How do I deal with this bickering? Do I ignore it? Do I reprimand them? Help! They are at it from morning to night!

A: If you have two children or more, you're going to have sibling rivalry, especially if their sex is the same or their basic temperaments are different. You can expect one or two noisy squabbles a day in even the best adjusted family.

This isn't all bad. A little friction helps children learn how to stand up for themselves, get rid of their bad feelings and resolve their problems. It's also rather fun (at least for them) and as natural as nature.

Watch a litter of puppies wake up from a snooze. They start scrambling on the mat, then chase each other, then invite real trouble with a snip at a paw or an ear. Dog mothers put a stop to this foolishness before it turns into full-scale warfare, and human mothers must do the same. That's what civilization is all about -- and civilization begins at home.

The rivalry between your children will lessen in time (although it will never completely disappear), but you have to step in if the atmosphere in your house gets bitter and intense or if the children tattle on each other routinely, hold grudges for days or weeks and see every small put-down as a calamity, or if they get violent or hurt each other.

There is a school of thought that believes parents should let a child beat on a special doll and pretend it's her sister, but that's hardly the way you want your children to learn how to settle their quarrels.

There are a few basic guidelines to follow.

Don't play favorites -- children weigh nuances with the precision of a chemist -- and don't compare one child to the other or say that little girls mustn't act that way, since the child's sexual identity should come from herself, not from you. Nor should you openly tell people that your children fight all the time. If they overhear you, they'll do their best to live up to their billing.

Instead, teach them, slowly and patiently, how to negotiate and compromise, while speaking their minds and standing up for their principles. Your children will learn these lessons if you treat them as individuals, recognize their special needs and sensitivities and give each one 10-15 minutes alone with you every day. This is when you talk -- and especially listen -- not even answering the phone or glancing at the paper.

It also helps if you chart the time and substance of their blowups. If they happen between 5 p.m. and 7 p.m. -- Arsenic Hour -- your children probably need a high protein snack around 4. Apple slices smeared with peanut butter can raise their blood sugar nicely.

This chart may also help you realize how many of their fights are over possessions and space. Tension should lessen if you give each child a special shelf for special toys and insist that each child ask permission to play with the other's toys.

You'll find other fights are born of boredom. If you give your children an unexpected story or a walk when they're still being good, they'll stay good a little longer, and they'll get your subtle message: Good behavior gets good attention.

And when they bicker and fight anyway, you'll find that no attention works best, since a referee is only paid in shrieks and squalls. By ignoring as much as you can, your children will learn to work out their own solutions.

This particularly goes for tattling, which a child does for attention. The next time one of your children tries to tattle to you, ask, "Is there any blood?"; "Is anyone hurt?"; "Is anything being destroyed?" And if she says no -- and you'll be surprised how often she will -- then refuse to hear any more about it, as curious as you might be. It won't be long before she finds that it's no fun to tattle to herself.

When the fights or the name-calling get serious, or when they seriously annoy you, quietly put each child in a separate room, away from you, and let them be until they (and you) calm down. Being alone is no fun for a young child, even for 15 minutes.

If they try to resume the scenario when they come back, have them return to their rooms for a few more minutes. Sometimes it takes a double-whammy to make a lesson work.

After any big fight, it's important that you have your children hug and make up with each other and with you. Children can't apologize until someone teaches them how.

You also can help them to show their love by teaching them to be thoughtful and protective of each other. Quietly remind one child to pick up a book for the other when she goes to the library or to bring home some of her cake from a birthday party. And when one goes on a trip without the other, have the traveler send postcards to her sister and bring a gift home to her. In a few years, you'll be able to let them visit relatives together for a few days.

The strength of a family lies in its bonding -- and it's never accidental.

Questions may be sent to P.O. Box 15310, Washington, D.C. 20003.