Y tu mamá is about two teenaged Mexican pals, Tenoch and Julio, one the upper-class son of a government minister (you know what that means) and the other the son of a single working mother. But Julio isn't a sympathetic prole; both boys are amoral sex-and-drug bangers, who convince Luisa, an older relative of Tenoch's, to go on an excursion with them to a paradisal beach they've made up to get her to say yes. (They search out Julio's sister at a leftist protest march in order to borrow her car.) In the enforced intimacy of the long road trip Luisa becomes disgusted with their male rivalry and their mixture of braggadocio and childishness. They're boors, but they're also thin-skinned boys. But they're also boors. The things they confess to when their feelings get hurt are shockingly degenerate.

Things go somewhat better once Luisa lays down rules. Rules are important ... but not taboos. Having exerted her authority she seduces both boys in turn and then pushes them to have sex with each other. I think the boys' bad behavior is so shocking because Cuarón shows no feeling for them. Who could find these thoughtless, weaselly-whiny, glazed-eyed stoners attractive? But in place of the agnostic candidness of a rowdy sensualist like the French director Bertrand Blier, Cuarón has didactic purpose. Thus, Y tu mamá doesn't celebrate the breakthrough of repression in the boys, but uses it as a means of punishing two little capitalist piglets who are too insensitive to draw any pleasure from what's on the other side of repression. Having sex with each other finally tears them apart in a way that fucking each other's girlfriends never would have.

The movie is gorgeously shot, certainly. Cuarón knows how to present a variety of settings in a style that's specific to each and yet unified overall. What's behind the unity, of course, is Cuarón's generalized disapproval. Whether we're in urban dwellings or rural villages or on the beach we're always aware of the shaping of exploitive economic and social relations. The beach, for instance, is where fishermen are displaced by resort hotels. To Cuarón escape is impossible because exploitation touches everyone everywhere you go, and besides, you bring your false consciousness with you.

Cuarón's moviemaking technique is impassioned, but his literary means are comparatively crude. Like such brilliantly shot but soft-headed left-wing classics as Sergei Eisenstein's Potemkin (1925) and Costa-Gavras's Z (1969), Y tu mamá is a visually and rhythmically convincing work, but, ay caramba, las palabras! At regular intervals, Cuarón mutes the soundtrack while a narrator relates a brief vignette associated with the location, generally having to do with some working-class misery that our boys are unaware of. Halfway through the movie these announcements had me laughing out loud because their self-seriousness had become both predictable and imitable, one of the prerequisites for camp.