Although it's poky, gimmicky and strictly nonessential, "Carbon Copy" may be enjoyed as a goodhearted anachronism. George Segal, more pensive and appealing than he's seemed in quite some time, stars as a melancholy corporate executive in Los Angeles who derives unexpected emotional renewal from an event that initially threatens social ruin -- the discovery that he's the father of a black son, the offspring of an interracial love affair unwisely and dishonorably abandoned back in college days at Northwestern.

Opening today at area theaters, "Carbon Copy" is an awkwardly wistful comic parable that harks back to the period of "Guess Who's Coming to Dinner," "The Landlord" and vintage Norman Lear.

Screenwriter Stanley Shapiro may have hoped to renew his career on a socially conscious note with "Carbon Copy." A tender, hopeful mood lingers at the fadeout, compensating to some extent for the unintentional condescension of the racial angle, which tends to perpetuate the notion that blacks exist mainly to redeem the sins of white folks, and the excessive silliness of the plot complications, which bottom out with the hero reduced to stoop labor while sharing grungy quarters in a Watts tenement with his long-lost boy. Retaining at least a glimmer of sentimental sincerity and dignity, "Carbon Copy" ultimately seems to have its heart in the right place.

The basic appeal of Shapiro's little fable derives from the idea that life affords second chances, the opportunity to start over and make amends for old mistakes and regrets. Segal's character, Walter Whitney, is reminded that he betrayed his feelings when he broke off with the mother of the cheerfully impertinent young man, Roger, played by Denzel Washington, who suddenly turns up to drop a couple of bombshells, revealing both his own existence and the recent death of his mother, a true heart who evidently pined away in faithful silence back in Evanston. The premise seems even more dubious when you're finally shown a snapshot of Roger's mother, a vision of adorability if there ever were one. Walter's remark about not being able to remember what she looked like suggests a mind-boggling absence of mind.

Nevertheless, the dubious situation has its symbolic uses. Acknowledging Roger becomes the first step in Walter's reaffirmation of independence and masculinity, which have been dwindling away during years of marital frustration and economic dependency. Walter's original sellout was marrying the boss' daughter. When he insists on taking Roger into his home, he quickly finds himself without a home or a job. These deprivations are perceived as blessings in disguise. Despite the temporary inconvenience and loss of status, Walter hasn't lost anything he really needs or values.

A borderline case, the movie expresses just enough emotional conviction to validate its optimistic theme, always on the edge of collapse from the pressure of facetiousness. I suspect it's Segal who makes the difference. Although Shapiro and director Michael Schultz are unreliable comic sensibilities, Segal recaptures the melancholy authenticity that used to make him a believable embodiment of restless, discontented middle-class husbands in movies like "Loving" and "Blume in Love." The events in the movie are usually ridiculous, but Segal inclines you to take Walter seriously. He really acts like a man who might be painfully conscious of a wasted life and self-respecting enough to make a new start.

Segal and Washington aren't a particularly amusing father-and-son match, temperamentally or physically, but they generate enough rapport to suggest the start of something friendly and satisfying. As Walter's frigid wife, Susan St. James can't finesse a caricature as limited in appeal as Cinderella's stepmother. On the other hand, Jack Warden, evolving into more and more of an old smoothie (he's the only amusing thing in "So Fine"), makes her father a serenely engaging comic monster. Shapiro has supplied him with admirably paternalistic lines. "You're a lucky man, Walter," he informs his son-in-law at one point. "Learn to trust unhappiness. Throw yourself into your work. I've never seen a happily married man who was worth a damn."