The smart one, the cute one, the shy one, and the funny one. Temperamentally, "The Sisterhood of the Traveling Pants" is like the Beatles, with jeans. Cinematically, it is like the Ya-Yas, with Livestrong bracelets.

More practically it is a SisterGood, falling short of SisterGreat, buoyed by Amber Tamblyn (as Tibby, the wry Goth) and America Ferrera (as Carmen, the effervescent intellectual) with passion, compassion and moxie that are tonic.

A resilient pair of thrift-shop denims unite the far-flung 16-year-olds through the long, lonely summer after sophomore year in high school, when they're apart for the first time since meeting in utero at their moms' prenatal yoga class.

Amazingly, these one-size-flatters-all jeans equally suit 5-foot voluptuous Carmen, 6-foot toothpick Bridget (Blake Lively), lanky Tibby, and minuscule Lena (Alexis Bledel).

It's no surprise that when the girls wear the pants (faithfully FedExed among the four throughout the summer), each finds it's like wrapping herself in the security blanket of her posse. The surprise is that the pants give her the courage to face that demon gnawing at her self-esteem, whether it's overcoming a father's estrangement, mother's suicide, friend's death, or terminal shyness.

Yes, there are cute boys - a Greek god Lena meets on the isle of Santorini, and a blond Adonis who coaches at Bridget's soccer camp. But, as "Sisterhood" celebrates the girl-sane over the boy-crazy, the guys are in the picture only to the extent that they help the girls address their issues.

Based on the first in the popular series of young-adult novels by Ann Brashares, "Sisterhood" is "Stand by Me" for girls, as sullen, plucky, melodramatic, exuberant, athletic, graceless, crafty, artistic, arrogant, modest, helpless and resourceful as its teenage heroines. This sisterhood contains multitudes, which is why so many readers are drawn to their stories. The conflicts here are considerably more compelling than snagging a prom date.

There is a lot that could go wrong in adapting material with more mood fluctuations than Ozzy Osbourne and more scenery than a James Bond movie. To the credit of screenwriters Delia Ephron and Elizabeth Chandler, director Ken Kwapis, and cinematographer John Bailey, the film maintains a consistency of tone.

When together, the girls shared intimacies, grief and joy, but it is while apart for the first time that they each reflect upon the very nature of friendship. They are friends not only because their mothers once were, but because each has a gift that the others lack, a gift that gives strength to the others - even in absentia.

And they are friends because they recognize how strength can mask weakness. Bridget is an awe-inspiring jock, but does she run so swiftly because she's running away from something? Lena is a talented artist, but does she study others so carefully to avoid studying herself?

One could wish that the Bridget and Lena story lines were as finely drawn as those involving Tibby and Carmen. But finally, what's not to like about a movie that warmly insists size doesn't matter, but soul and friendship do?