See Paul (Mark Ruffalo) harvest his lush vegetable garden to provide ingredients for his luscious organic restaurant in Los Angeles. Paul's fecundity is a wonder. Where he scatters seed, there is abundance.

In The Kids Are All Right, Lisa Cholodenko's sharp and seriously funny portrait of an American family, Paul is about to learn that a little deposit he made at the sperm bank 18 years ago has yielded two strapping teenagers.

Paul is the bio-dad of Joni (Mia Wasikowska), 18, and Laser (Josh Hutcherson), 15. His sperm impregnated each of their lesbian mothers: Nic (Annette Bening), a driven gynecologist, gave birth to Joni. Jules (Julianne Moore), an artistic type looking for a creative outlet, bore Laser.

Here are five gifted actors at the top of their games as five characters in search of what makes a family.

Unbeknownst to "the moms," the somewhat rootless Laser persuades the grounded Joni to investigate the family tree. First they meet Paul, affable hipster and overripe Peter Pan. Then they invite him to meet the women with whom he has such a consequential - and unrecognized - relationship.

Paul, the unstable particle introduced to this relatively stable environment, triggers a chain reaction in the family he inadvertently helped create.

What starts as Laser's identity crisis becomes the family identity crisis. Paul's presence exposes the fault lines in Nic and Jules' marriage. While the moms worry that Paul might undermine their parental authority, he's also able to influence "the kids" in positive ways, too.

Cholodenko is the keen-eyed social satirist who made High Art and Laurel Canyon, movies about the lure of bohemia to traditional types. Kids, though, is the reverse: a film about the lure of tradition to a bohemian. The twist: That the family-values advocates are a lesbian couple and the outsider is the heterosexual entrepreneur.

Paul is one of those free spirits who can't commit to dinner, let alone a woman. But when he does come to a family meal with the kids and the moms, he feels . . . connected in a way that's new for him.

Cholodenko (who wrote the screenplay with Stuart Blumberg) is a filmmaker who, without heroizing or vilifying, tells multicharacter stories from multiple perspectives.

As the story progresses, each figure is the central character for a scene or two. While Cholodenko makes them all sympathetic, she's not above slyly satirizing Nic's politically correct jargon, Jules' habit of turning nouns into adjectives like "trellis-y," and Paul's all-purpose default, "cool."

The cumulative result is a movie diverse and bountiful as Paul's garden. It's sexy and smart, rueful and hopeful, and, like its beautifully drawn characters, one of a kind.EndText

Contact movie critic Carrie Rickey at 215-854-5402 or crickey@phillynews.com. Read her blog, "Flickgrrl," at http://www.philly.com/philly/blogs/flickgrrl/.