Is it too soon to welcome a New Mexican Cinema? After last year's "Amores Perros," that witty and profound look at Mexico today, we now have "Y Tu Mamá También" ("And Your Mama, Too"), a correspondingly insightful look at everything from teen sexuality to fractured marriages to the desperate split in Mexican culture between rich and poor.

Director and co-writer Alfonso Cuarón, who has worked both in Mexico and the United States ("Great Expectations" and "A Little Princess") shows an easy mastery of his art form, turning what might have been only a simple soft-core porn film or a blatant political tract into a perceptive movie about growing up and living in a fractured society.

We meet two 17-year-old best friends in Mexico City, Julio and Tenoch. Julio is played by Gael García Bernal, who was in love with his brother's wife in "Amores Perros," and Diego Luna is Tenoch. Their girlfriends are leaving them for the summer to travel in Europe but their hormones never stop raging; they've been left at home, frustrated and horny. They meet Luisa (Maribel Verdú), ten years older and infinitely wiser. She's the wife of a cousin of Tenoch. She's Spanish and wants to see more of Mexico. Her husband is out of town, and in a bizarre, drunken phone call he confesses that he's been unfaithful. Stung, she accepts the boys' invitation to drive to a supposedly fabulous beach, called 'Heaven's Mouth,' whose glories are only enhanced by the fact that it doesn't exist except in their minds. The boys decide that they'll just get to the coast and figure something out from there.

The three pile into Julio's borrowed station wagon and set out on what will be their odyssey toward both adulthood and a comprehension of what it means to live and to die. The film treads lightly over difficult questions; on the drive to the coast the car passes frequent roadside attractions: everything from armed soldiers questioning peasants to crosses marking the traffic dead, from a herd of steers crossing in front of the car to a roadblock of flowers with locals asking a donation for the 'Queen,' a local girl dressed as the Virgin. An offscreen narrator keeps us at a respectable distance from all of this, filling in the gaps.

But arrive they do, and the beach turns out to be the real 'Heaven's Mouth,' beautiful and comforting. The three are taken in hand by a local fisherman and his family, though even here there is no paradise: the narrator tells us that a new luxury hotel will be built in the nearby nature reserve; the fisherman will lose his livelihood and will end up as a janitor in that hotel.

Nor has the film forgotten its date with a larger question, the one of life and death. We will learn secrets that pull us back from the giddiest of heights, to the acknowledgment that nothing in the world is without its cost.

Since much of "Y Tu Mamá También" is concerned with the education of the two boys, both sexual and otherwise, a great deal of it is erotic, in the best sense of that word; that is, it treats sex as what sex is: orgasmic, sometimes scary, and usually really exciting. Luisa, older and wiser than the boys, is also a very willing partner to them, and in a beautiful performance (you may remember Maribel Verdú as the sexy daughter in "Belle Epoque") she is the essence of senuality.

Here I need to echo what the critic Roger Ebert has said in his review of the film: the MPAA rating system infantalizes American films. This movie could never have been made in the United States (it's been released without a rating and so is condemned to play in limited venues in just a few cities). Where our society lets us be free to buy novels and poetry that are erotic, and to see dance and theatre that are erotic, an agreement between the studios and the theatre owners has ensured that in most of America we are not allowed to see films like this. The studios won't make them, the theatres won't show them, and most newspapers won't allow them to be advertised.