A new Argentinian film has sparked a debate about intersexuality and gender ambiguity, and whether it is possible to live as a hermaphodite

PERHAPS ONE OF art's most valuable qualities is its ability to unsettle us, particularly when we're not quite sure why. Long after the credits roll on XXY, a film by young Argentinian director Lucia Puenzo, one scene in particular lingers. On a deserted beach in Uruguay, 15-year-old Alex strives to attract the attention of Alvaro, the teenage son of friends of her parents. As he lies on the beach, headphones on, sketching, Alex stamps around in frustrated circles, windmilling a stick ever closer and closer to his prone body.

The stick is not hefty enough to do any real damage, nor is the beautiful, fragile Alex truly threatening, yet the scene is unbearably tense. As Alex swishes her stick and Alvaro lies on the beach oblivious, something preys on us.

Alex, as played by the wonderful Inés Efron, is feminine but only ambiguously so. She wears shorts with over-sized gumboots on her long, gangly legs. We sense that she is trying to flirt with Alvaro, yet she goes about it as a teenage boy would, her whirling stick and her stomping boots a clumsily aggressive act of desire.

Just moments later, the pair are naked and Alvaro discovers what has previously only been hinted at: Alex is neither male nor female, but what was once called a hermaphrodite and is now more frequently termed "intersex". In other words, she has genetic and genital characteristics of both a man and a woman.

In the flesh, 25-year-old Inés Efron is much girlier than her character, all clinking earrings and butterfly lashes. She and Martín Piroyansky, who plays Alvaro, are in Europe to speak at one of the many film festivals which picked up XXY after it won the Critics' Choice Award at the Cannes Film Festival last year.

In Ireland, XXY is an exclusive at the reborn Light House Cinema, when it opens in Smithfield Square in Dublin tomorrow.

Reaction to the film has been far in excess of anything its director or stars imagined.

"It got huge audiences in Argentina," Efron says softly. "The kind of audiences only commercial movies get."

"That's something I admire about the movie," Piroyansky agrees. "It reaches everybody. We go to festivals, they like it. We open at cineplexes in Argentina, they like it. The United States, Europe . . ."

Wherever it opens, XXY kicks off debate, not because it shocks but because it opens up the wider question of whether a "third sex" is possible, one which is neither female nor male, but simultaneously both and neither.

For Lucia Puenzo, it was a short story by Argentinian writer Sergio Bizzio which opened up that dilemma. Puenzo - a novelist of some standing, and daughter of Oscar- winning director Luis Puenzo - did months of research, talking to doctors, geneticists, the intersex community and their parents before embarking on the project.

"When I began writing the script for XXY," she states, "I was surprised by the almost total lack of stories on the subject."

GIVEN THAT ONE birth in 2,000 shows some signs of what doctors describe as "genital ambiguity", such an absence is surprising. Visual representations abound in the art of ancient Greece, most famously in the Louvre's Borghese Hermaphroditus, which depicts the son of Hermes and Aphrodite lolling coyly on a sofa, both breasts and genitals exposed.

More recently, American writer Jeffrey Eugenides had a surprise bestseller with Middlesex, a rip-roaring tale of how Calliope became Cal. After years spent as both a man and a woman, Calliope/Cal concludes: "Contrary to popular opinion, gender is not all that important."

In XXY, Alex's parents move from the prying eyes of Buenos Aires to a remote cottage in Uruguay and do not consent to genital reconfiguration surgery, an operation which was, until recently, standard medical practice.

Their idea is that Alex will chose whether she feels male or female when she matures. Instead, the film questions whether that's a decision which needs to be made at all. Might a person not be desired just as she/he is? Is invasive surgery not just a response to the widespread unease that sexual ambiguity provokes? Yet it would be a mistake to view XXY as a kind of for-and-against docudrama, as, in truth, it is only about hermaphrodites in the same way that Casablanca is about Nazi- occupied Morocco.

Strong performances, not only from Piroyansky and Efron but also from old hands such as Ricardo Darin, make it a character-driven piece dealing with the intricacies of human desire and identity.

For Inés Efron, XXY is first and foremost a coming-of-age story, while her co-star, Martín Piroyansky, feels it's all about their romance.

"The hermaphrodite issue is always there," Piroyansky points out. "But really it's a love story. Gender ambiguity is a condition Alex has, but where people connect with the movie is the love between these two characters."

"That's the universal thing," says Efron. "I like when I have the opportunity to deal with that moment of adolescence when you don't know who you are, and you feel so full of existential pain."

WHEN IT CAME TO inhabiting the complex character of Alex, Puenzo suggested Efron think about her body. "Lucia told me to manifest my character physically, by shifting my body, by being conscious of how I held my shoulders, my arms, my head."

Arriving at the film shoot a week early, Efron spent hours creating intricate painted diaries which eventually ended up part of the film as Alex's journals.

"My mind went down into my body," she says simply. Before the film went on general release in Argentina, Puenzo took the precaution of showing it to an invited audience from the intersex community.

"If they were against it, it wouldn't have worked as a film," Efron says, "But they accepted it. Afterwards, several people said to me they liked it because they'd never seen a film about intersexuality which was also erotic."

Understandably, much attention has focused on Efron, whose performance sustains the whole film, and who, in person, resembles so little her awkward, tomboyish character.

"People ask me all the time: what do you think Alex's life will be like, how will she live? But I can't answer that. As an actor, I just went with her. If the audience has questions, that's good, but I don't know how to answer them."

XXY opens at the Light House Cinema, Smithfield Square, Dublin, tomorrow