Endearing 'Kids' heartfelt tale of growing up

Lisa Cholodenko's wonderful "The Kids Are All Right" is about many things, but at its heart it's about a girl who's ready to fly away from her family's cozy L.A. nest.

Eighteen-year-old Joni (Mia Wasikowska, of "Alice in Wonderland"), her pale face framed by sheets of hair that you want to brush away, loves her two moms, Nic (Annette Bening) and Jules (Julianne Moore), but she's easily irritated by them.

A recent high-school graduate, she's beginning to assert her independence, and does so in an unusual way: At the urging of her younger brother Laser (Josh Hutcherson), she contacts Paul (Mark Ruffalo), the biological father/sperm donor whom the two kids have never met.

And that's the beauty of Cholodenko's film: It's not about Mia coming to terms with her gay parents, but with her straight nonparent.

Her family is, refreshingly, presented with utter casualness: They are, in nearly all respects, just like any other family, and probably happier than most.

The acting in this film is so good, across the board, that it doesn't feel like acting; we're simply watching a family going through some drama (and comedy) over a summer before its eldest child leaves for college. Bening and Moore effortlessly make us believe that they're a long-in-love couple, and that, whatever happens, the strong unit they've created will survive.

Ruffalo has a reckless wistfulness that's endearing, and Hutcherson perfectly captures that spidery uncertainty of 15-year-old boys. But it's ultimately Wasikowska's gently resolute expression that stays with us at the end as she tentatively takes her first steps toward grown-up life, secure that she is greatly loved.