Weddings are supposed to be joyful affairs, but though the one depicted here eventually turns out that way, there are lots of problems along the way. In portraying the run-up to the Los Angeles nuptials between a Mexican-American girl and an African-American guy, “Our Family Wedding” becomes a crude culture clash sitcom in which both groups lose—along with those of us who belong to neither. It feels like one of those quickly-busted series Fox foisted on viewers at the very beginning of the network’s existence.

The prospective groom is Marcus Boyd (Lance Gross), a doctor who recently completed his studies in New York City and plans to move overseas to do humanitarian work. His fiancée is Lucia Ramirez (America Ferrara), who not only hadn’t told her parents, auto repair shop owner Miguel (Carlos Mencia) and Sonia (Diana Maria Riva), about Marcus, but has also failed to inform them that she dropped out of law school to become a teacher.

To give you some idea of how bad the script is, Marcus’ father Brad (Forest Whitaker)—a divorced, lady-chasing disk jockey—and Miguel meet “by accident” when the latter shows up to tow away the former’s illegally parked car and the two men get into a shouting match tinged with racial overtones. That sort of coincidence is so likely in a metropolitan area of nearly eighteen million people! But it does set up a tense first family gathering, of course—which is all that’s important to our screenwriters.

The movie is ultimately about overcoming obstacles to true love—in terms not only of the marital plans of Lucia and Marcus, but of the strains in the older Ramirez’s marriage, and of Brad’s inability to commit to his long-time girlfriend Angela (Regina King). There’s never the slightest doubt that things will turn out nicely for everybody. But you can be sure that there will be lots of idiotic farce along the way, much of it tinged with ethnic would-be humor. Among the worst sequences are one in which Brad imagines the disasters that might befall the wedding guests while the family discusses seat placements and another in which he and Miguel go to a night club to scope out a DJ and get predictably smashed.

But none of the earlier scenes can compete with the wedding itself, marked by the introduction of an extremely randy goat. How, you might ask, does a goat wind up at Brad’s palatial abode? Well, Lucia’s intrusive grandma (Lupe Ontiveros)—just the worst of the Hispanic stereotypes on display (though to be fair they’re balanced by African-American ones)—insists on a traditional Mexican ceremony, which must include the sacrifice of the animal. As if that weren’t bad enough, the goat breaks into Brad’s bathroom, eats a bottle of Viagra and…well, the resultant scene is something Whitaker will be anxious to suppress, and you will too.

Otherwise Whitaker’s easily the best thing about the movie, though both King, who’s nicely understated, and the personable Ferrera run him close, and Gross is okay, though his character is a cipher. As to the worst, after the script it’s definitely Mencia, who as an actor is a fine stand-up comic. It’s the sort of performance that’s genuinely painful to watch.

Subpar production values add to the odor of failed sitcom, and the mix of pop tunes and original music by Transcendere that make up the background score comes on much too strong.

One longs for a touch of Norman Lear-like comic insight at some point in “Our Family Wedding,” but in vain. The only consolation for Mexican-Americans and African-Americans is that the movie would be equally terrible if the script had been entirely scrubbed of its ethnic elements. It would still be as bad as “Bride Wars” and “License to Wed”—another movie so awful it might put you off the idea of getting hitched at all.