Fighting kids. It's the last week of summer and siblings everywhere are knocking heads while parents are shaking theirs. The opening day of school shines like a promising beacon - the end of vacation is in sight.

What's all the bickering about? Certainly a great deal of it is normal. One of the pluses of growing up with siblings is learning how to negotiate, how to provoke, how to maneuver, how to assert and when it's the better part of valor to retreat from the field. When fights between siblings are fairly equal, with no one the constant winner or loser; when no one gets regularly or really hurt, there is in fact a lot of value in even the bickering. Kids are figuring out human relationships on the most basic of levels.

In healthy families, periods of arguing alternate with long periods of cooperative play as well as times when each child can expect to be able to enjoy time alone. Sibs can count on each other to rally to their defense against outsiders and even against parents at times even though they also often duke it out among themselves. Most importantly, children who are growing in a healthy way are genuinely concerned and apologetic if things go too far and someone is really hurt.

But some fighting goes beyond what is "normal" or helpful as a learning activity. John and Meg (not their real names) came to see me last month with their three boys, ages 11, 9, and 8. As they came up the stairs, the boys smashed each other into the walls, complained to their parents, yelled at each other and generally made a noisy and alarming entrance. John made some half-hearted attempts to stop them. Meg looked dazed. "They're like this all the time," she said.

Why can't two nice and apparently reasonable adults stop the fighting? Further discussion revealed that John had an idea that "boys will be boys" and so he often didn't recognize when things were getting out of hand until it was too late and someone got hurt. He had grown up with largely absent parents so had no model for how to break it up, nor was he entirely convinced that it was his job to do so. Meg, on the other hand, didn't want to be the authoritarian parent that her parents had been so she continually tried to reason with her sons. Meanwhile, the kids got worse and worse.

Of most concern to me was that none of the boys really felt safe with his own brothers. In a quiet moment during the session, each confessed that they didn't feel as though they were liked by their siblings or that their siblings would help them.

It's not that these parents hadn't tried. Meg told me about countless approaches she had read about and instituted. She would try something and, if it didn't work, she and John would end up arguing about whether that was any way to stop the fighting.

What can I suggest to help? First, these parents need confirmation that this level of fighting is not normal behavior for boys (or for girls either). Next, John and Meg need to work out a clear agreement between themselves about what is and is not acceptable behavior and what they will do about it.

John needs to understand that boys can be strong without being hurtful to each other. Meg needs to understand that one can rarely reason a child out of something that isn't reasonable in the first place.

It almost doesn't matter what system of discipline these parents choose. Most of the articles and books that Meg has been reading do offer some solid information. The trouble with Meg's attempts at "discipline method of the week" is that the kids have come to understand that she will abandon it at the first failure. Further, John hasn't been there to help her when she waivers.

With John's backing, Meg could hang in longer and give a consistent message. With Meg's backing, John could take a more active role as one of the adults in charge. When parents back each other, the kids get a model of family members sticking up for each other. And when parents back each other in keeping everyone safe, children like these can feel secure in their own home.

Finally, it's not enough to stop negative behavior. These kids need lessons in cooperation. Meg and John need to start insisting that their sons work together as a team - at least sometimes. Practicing sports in the yard, building something together , playing board games, cleaning up after dinner together, are all good forums for learning to cooperate. Any time someone starts a fight, Meg and John can halt the action for a few minutes until everyone can regroup and try again.

The key to turning the level of fighting back to something normal is the parents' commitment to the project. Essentially, Meg and John have only two choices. They can let things continue to disintegrate and live in a constantly embattled family or they can work to make changes. Neither choice is easy.

If they do commit to taking charge, it will take a number of months of consistent effort for the children to believe that there really is a new order in the household. But it's been my experience that when parents are clear, kids are only relieved and respond well.

Dr. Marie advises:

To help your children be friendly with each other . . .

• Decide that a first priority in your household is that everyone will feel safe in his or her own home.

• Understand that it is neither necessary nor normal for siblings to be violent with each other.

• Choose a good method for maintaining order in your home and stick to it.

• Find ways to support your spouse

• Model team work. Do things together as a family.