It is not an unnoticed fact, but one still worth mentioning, because it is fun, that the career of Alfonso Cuarón repeated itself in a weirdly specific way. First, in 1991, he made Soló con tu pareja, a Mexican film with political overtones, that features a lot of sex. Then he went to America and made A Little Princess, a kids' movie based on a well-liked work of children's literature. He then made Great Expectations, a film for adults adapted, very loosely, from a novel.

In 2001, he made another Mexican film with political overtones, that features a lot of hugely explicit sex. Then he went back to America and made a kid's movie based on the most popular work of children's literature in the world. He then made a film for adults adapted from a novel so loosely that it barely counts any more.

The moral of the story: fuck you, Gravity.

So let's now turn to that Mexican film with political overtones and sex. The second one, I mean. It is a certain Y tu mamá también, and it's the film where Cuarón first gained acclaim in and of himself, rather than as the very sincere and talented journeyman director of A Little Princess (Soló con tu pareja not being widely available outside of Mexico until deep into the 2000s, and Great Expectations being largely disliked). Not coincidentally, it's also the film where Cuarón really turned into the specific auteur that we are inclined to describe him as in a post-Children of Men world, which was a deliberate act of will. The filmmaker hasn't exactly trumpeted the story, but he's not ashamed to tell of it either (the timing's too perfect not to share this recent interview), that making Great Expectations was not a good experience: he was not terribly enthusiastic about the results, and for his return to the mother country, made a conscious choice to open up his aesthetic and make things in a way that the Hollywood apparatus would have made difficult.

The results are revelatory. Let's not mince words - revelafuckingtory. In all the ways I can think of, Y tu mamá también is a monumental, transformational motion picture, challenging the viewer and changing the way you think of movies being put together, the stories they can tell, and the ramifications of those stories. To begin with, it has what might well be the single best depiction of adolescent sexuality in any film of the 21st Century, treating with candid humor and perfect seriousness one of the subjects that is quintessentially Off Limits. For all that sexed-up teenagers being horny is a commonplace occurrence to the point that it's just wallpaper now, grappling with teens as psychological actors ho have sexual urges and needs, rather than wacky boner jokes. It even depicts, with jaw-dropping plainness and documentarylike accuracy, the physicality of teen sex, requiring the viewer to consider with non-prurient interest the fact that 18-year-olds (the actors, of course, were all legal adults) do in fact do these things: they perform and receive oral sex, they ejaculate. Oh, how they ejaculate, in what is unquestionably the most shocking scene of the film, all the more so because the film itself isn't looking to shock us, but simply present the characters' reality.

While we're still on sex: Y tu mamá también is, if anything, even more transgressive and shocking for the way that it discusses and analyses gendered approaches to sexual pleasure. The very first line of the film finds an 18-year-old boy in the midst of sex staking a claim on his girlfriend's body, and viewed from the right angle, the conflict for the rest of the film is predicted on unconscious male privilege in a macho society finding itself at odds with strong, self-directed female self will; after the legendary masturbating-into-a-pool scene,the most commanding and sexually blunt scenes in the film involve a 30-ish woman giving instructions to teen boys ten years her junior as to how to best please a woman sexually, finding their clumsiness charming right up until she abruptly and angrily finds it selfish and cold.

That is, mind you, the conflict viewed from the right angle. From a slightly different one... oh, let me just write a damn plot synopsis already, so I can start using specifics. Best friends Julio Zapata (Gael García Bernal) and Tenoch Iturbide (Diego Luna) have just barely graduated from high school in Mexico City, and their respective girlfriends, Cecilia (María Aura) and Ana (Ana López Mercado), are traveling to Europe for the summer to celebrate, leaving the boys to do absolutely nothing. Just hang around, jerking off, smoking pot, eschewing responsibility. It comes to pass that at a wedding in which all the important members of Tenoch's father's political party are in attendance (the elder Iturbide is a high-ranking politician), they meet Luisa Cortés (Maribel Verdú), the Spanish-born wife of Tenoch's writer cousin. With the horny certitude of 18-year-olds, the boys try to flirt with her by inventing a fantastic, pristine beach far away from the city, though the woman very coolly and wittily shuts them both down.

A little while later, her husband confesses that he's been having an affair, begging forgiveness. Stunned and mad, Luisa immediately contacts the boys and agrees to go on their trip. The facts that the Boca de Cielo beach doesn't exist, and that neither of them knows much about the world outside of Mexico City, are of minimal concern to either of the young men, what with a smoking hot older woman willing to spend five days alone in a car with them, and so, with the world's shittiest route planned out, the three plunge in to the Mexican countryside, and it's here that Cuarón and his screenwriter brother Carlos get to explore all kinds of fraught interpersonal relationships and sociopolitical concerns, in ways that never stop seeming supple, complex, and sophisticated, no matter how many times you see it.

Broadly, Y tu mamá también is about class and gender, both of them awfully large terms, which makes it all the more impressive how very much the film is able to get to in its jam-packed 106-minutes. There are all sorts of nifty divisions between the characters: Luisa is European, where Julio and Tenoch are Mexican; Tenoch is upper-class, Julio is lower-middle-class, Luisa has risen steadily from isolated poverty to something that can easily inhabit the upper class without being part of it. With the film depicting a specific, greatly significant moment in Mexican political history, it's this latter division that especially drives the movie, which, viewed from the other best angle, is about how class divisions that seem totally frivolous in adolescence start to fester and become big and nasty the more of an adult you become. It's not prescriptive: though there seems little reason to doubt that the filmmakers are sympathetic to the underclasses and the leftists (there's a haunting little aside involving a fisherman stripped of his livelihood that's one of the best criticisms of capitalist progress ever filmed), but that's not really the focus. Instead, it's on how class represents not just having and not-having, but an entire code of thinking about the world, and one's place in it. The jealousy and self-abnegation on Julio's side, and the superior contempt on Tenoch's, are very slowly teased out across the movie, in any number of ways, from screaming match where both boys use class-loaded words, to the narrator's blithe comparison of how the two boys use the toilet at each other's house: Julio lights a match to make sure that his stink doesn't hang around, while Tenoch raises the seat with his foot, to avoid touching it with his skin. It's a brilliant line: entirely illustrative of the exact point the Cuaróns want to put across, while feeling quite authentic to the experience of the two scatologically-obsessed characters.

Oh, and the narrator: mustn't forget to mention him. Voiced by Daniel Giménez Cacho in the crisp, impersonal tones of a newscaster, the narration in the film is its quintessential formal element, offering up a thick slice of ironic distance between us and the action (every time the narrator speaks, the ambient noise cuts out completely; frequently, this is as jarring to the film's created reality and narrative momentum as '60s-era Jean-Luc Godard at his most caustically formalist), dashing the idea of the film's realism even as it incalculably deepens its world. Frequently, the narrator has nothing to say about the plot at all, but to call our attention to some aspect of life, or some political event, that the main characters do not notice or care about, creating the sense that there is a bigger world than what is depicted in the film and emphasising the small, trivial focus of the protagonists on nothing bigger than their own impulses and urges.

Still, artificial or not, trivial or not, the three leads of Y tu mamá también are an especially rewarding set of characters to spend time with. They're not always likable; they're typically not likable, in the case of the boys. But they are powerfully authentic, they exude vitality, they have the ability to think, even when they're thinking about how to justify not thinking. Their behaviors are both heavily laden with symbolism about age, gender roles, and the political history of Mexico (the character names are pointedly metaphorical: Tenoch, a 14th Century Aztec ruler - ancient tradition, conservatism. Zapata, the 20th Century revolutionary - class awareness, radical leftism. Cortés, the Spanish explore - the European who vitalises the Mexicans at the cost of destroying them), and the filmmakers are overt in linking the boys' coming-of-age to the 2000 elections that radically shifted Mexico's political fortunes, but they also seem like exactly who they are: two cocksure teen boys and one increasingly regretful adult woman, playing each other against one another, so wrapped up in their little drama that a transforming Mexico passes them without their noticing. The performances are so complete and natural and lived-in that it hardly seems possible to talk about them using the vocabulary of acting. Luna, García Bernal, and particularly Verdú are so confident in their bodies, clothed and unclothed, active and passive, that even while they've all become much more famous in the years since the film was new, there's literally not a single scene where I'm thinking about the construction of characters, just the characters themselves.

The film is about the characters and the world and the way they interact with it and each other; and so it is right and good that it should boast such keen visual depiction of that flow between person and space, in the most stylistically radical by far of all the movies that Cuarón and cinematographer Emmanuel Lubezki had made to that point. Look at the handheld camera and graininess, and you would say that they were going for a kind of documentaryrealism; you would be right. Look at the way that Lubezki films landscapes and cityscapes (and there are many of both in this film) with a bleeding-out mistiness, and you would say that they were going for romanticism or impressionism; you would also be right. Look at the frequent long takes, particularly the ones that glide along invisibly as the car drives endlessly down the highway, or the fantastic one near the film's end where Luisa steps over to a jukebox and the camera follows her, at which point Verdú looks straight into the lens and walks the camera back, and you would say a lot of things, maybe; "what sort of eldritch geniuses came up with that shot, culminating in the jackhammer-like impact of that three-way hug?" is one of the things I said, the first time I saw it. Oh, I'm lying, every time I've seen it. But the long tracking shots that only now firmly assert themselves in Cuarón and Lubezki's shared toolkit are absolutely essential to Y tu mamá también; they create its sense of flow, of forward momentum, of a continuous space (call it the world, call it Mexico, or just call it the the unified space between these characters), and of a passionate, probing desire to explore that space. It's positively Renoirvian (Renoiresque?) how the filmmakers use the camera to not depict the characters, but to wander around their homes and the places they find themselves, telling us so much more about how the world works and how people live by soaking in details indiscriminately than could ever happen with just another conversation in two-shot.

Basically, this film is a masterpiece: a sexual masterpiece, a social masterpiece, an aesthetic masterpiece, a psychological masterpiece. And yet it's not, because "masterpiece" implies that it wasn't ever topped, which totally happened, when next Cuarón and Lubezki trained their camera on a world of people in transition and turmoil; but let's not get ahead of ourselves. Y tu mamá también is flawless if that word applies to anything in art, and just because the director made another flawless film, that takes away nothing of the achievement of this one, his coming-out party as one of the most interesting and vital international filmmakers of the brand new century.