Q.My problem (and I emphasize the word "my") involves my 4-year-old son.

Our "miracle baby" was a preemie -- under 3 pounds -- and has always had intense attention to take care of his developmental lag. He now has speech therapy twice a week but other than that he has caught up beautifully.

This has made us pretty protective of him (much more than we are of our 15-month-old son) but even so, he has begun to detach himself from his dad and me. He is now in nursery school three mornings a week, going with his best friend. However, my boy is in the younger group of 4-year-olds, while his friend is in the older one.

Now his friend has a new friend and, as you might expect, it is very hard for the three boys to play together. Although my son gets along with the new boy all right if they are alone together, the trouble comes when they are in a threesome. That's when the other two boys, who are both strong-willed, go after my son. The new boy hits my son's friend, who in turn hits my son, and then my son takes it out on his little brother.

When I stepped in recently to stop some hitting, the new child called me "poo-poo head." His mother said, "He calls everyone that nowadays."

I'm not used to this.

When children play in our yard everyone is a friend and we talk about our feelings. I don't allow play that intentionally hurts another child or let children call anyone (especially adults) "poo-poo head" or "stupid."

As an elementary school teacher, I feel it is important for children to get along with each other and with adults and have tried to teach my son the importance of caring, sharing and manners. (Yes, I demand "please," "thank you," etc.)

I know I can't impose my values on others, nor do I need to question mine. But how much do I interfere? Should I step back?

*A. Surely nothing pains a parent more than watching other children turn against her child, but some rejection is inevitable, especially when one child is a little less mature than the others.

You have to learn to take this in stride, and with a little humor, too. The new child may call everybody "poo-poo head" but it won't be long before your own son does some name-calling as well. Bathroom language and scatological jokes begin at around 4 and last for several years. With luck, you won't hear it most of the time, or at least you can pretend that you don't. That's the way it is with parenthood. You spend so many years looking the other way, you feel as if you have a permanent stiff neck.

Basically, parents overlook what they can, discipline when they must and keep on teaching good manners, but you can't be heavy-handed with any of this. For all their bravado, children are exquisitely sensitive creatures. To tell them what to say and how to act, over and over, would be bad manners on your part and an abuse of your power: Parents are so much bigger and wiser than children and so important to them.

Repetition is also nonproductive. It just oils the backs of those ducklings until everything you say rolls right off. As you know from your work in the classroom, children learn best by doing, not by listening.

You have to expect and appreciate (and use) good manners in order to get them. If, for instance, you stand in front of a door with your child, without pushing it open or asking a child to do it, he'll do the pushing himself. That's when you slip through first, fast as a flash, and say, "Thank you so much for opening the door for me!" as you hold it open for him. Or you compliment a child for being funny (if he's not being foul), so he'll act that way again. Children like compliments much more than they admit.

Your little troika will also behave better if you restrict their playtime more, by having your child play with only one friend at a time, or with three others. Children always play better in pairs.

Although this new boy may be more than you can handle, he and your son deserve the chance to build a relationship together, which may be possible if he's invited to visit alone. When there is trouble -- and there will be trouble with any children -- take particular care to talk with this guest quietly and in private. He'll have less to rebel about.

Once this child knows your rules and tries to live by them, set up a foursome with your son's old friend and one extra friend. This child should be one of several you invite to visit your son from time to time, for he needs a wider circle of playmates now. He can draw on them for support when his best friend drops him for somebody new, which happens throughout childhood. You just can't expect children to stay constant through all the changes that growing up requires.

And as these children change, their parents must change, too.

Yes, it's time to step back, loosen up and start letting your little boy go.

This is the hardest job a parent ever has and the most rewarding one. The child who has permission to leave is the one who always comes back.