Probably the most important thing kids learn is how to have peer relationships. As a parent, you can't do this, because you and your child aren't equals.

For example, when you're sitting on your family room floor and your very young child asks you to pass him the blocks, you probably hand them right over. If your child is sitting with a peer and asks the same thing, though, he might not get what he wants.

To succeed, your child will need to learn strategies for getting what he wants. For example, he might simply yank the toy out of his friend's hand. If he does that, he may learn that it's not the best way of getting what he wants because it leads to fighting and time-outs. The successful child will learn that he needs to negotiate a trade, to wait patiently, or to find something else equally fun to play with.

Friends also provide emotional support, something that is part of the foundation of healthy adulthood. You can't be with your child on the elementary school playground or at the high school dance. Your child's friends will be the ones to stick up for her, to include her in games, and later, to tell her she looks great even if her lousy prom date wanders off instead of dancing with her.

Friends also help your children learn. Friends solve problems together, imitate each other, and pass on knowledge (such as how to jump rope or speak pig-Latin).

Some experts believe that the single biggest predictor of your child's success later in life is her ability to make friends. In fact, they claim it's even more important than IQ and grades.

This doesn't mean that the kids who are most popular in school do the best later on in life. What matters is not the number of friends a child has but rather the quality of the relationships.

This is good news for those of us who hate to think that popularity really is the Holy Grail of childhood and adolescence. While it's true that popularity has many advantages, and that many popular kids really are nice people--and not just the best dressed or best looking--it's better to have a few good friends than to have the admiration of the masses.