“Transamerica” tries to accomplish the admirable but not easily achievable job of telling a story that's at once universal and particular, at once conservative and ultra-modern. Offering an examination of transsexuality, with certain realities discussed unabashedly, writer-director Duncan Tucker wears his liberal ideology on his sleeves.

Challenging the very notion of what's normal, “Transamerica” suggests that there is no such thing as normality anymore, and that regardless of gender and sexual orientation, what binds us as humans is our need for family, love, and home. Hence, what could have been a sharper anatomy of the increasingly popular phenomenon of transsexuality becomes a rather sentimental parent-child melodrama, one notch above the level of TV Movie of the Week.

Over the past two years, there have been several films about the theme of unexpected fatherhood, including Jim Jarmusch' “Broken Flowers,” Wim Wenders' “Don't Come Knocking,” and Jean-Pierre and Luc Dardenne's “L'Enfant,” all of which premiered at the Festival de Cannes. In “Transamerica,” which belongs to this sub-genre, the reluctant, curious father who learns he has a son just happens to be a woman. Is is reflection of the zeitgeist A mere coincidence

Though the main character is transsexual, “Transamerica” is not exactly about transsexuality in the way that the courageous Sundance documentary, “Southern Comfort,” was, in 2001. At heart, it's an old-fashioned story about a parent and her/his child, and the tying bonds of family. Despite the fact that the two protagonists in the film are anything but familiar, the plot is structured along the familiar lines of classic American road movies about odd couples. With varying degree of success, “Transamerica” transports viewers into the minds and hearts of two victimized individuals ordinarily looked upon (and looked down at) as outsiders, if not outright deviant.

For biological and psychological reasons, transsexuals change their sex from either man to woman (the more common pattern) or from woman to man. It's a painful, difficult process that requires the permission of doctors and psychiatric professionals. Indeed, changing one's sex involves an assortment of biological, legal, and cultural issues. Instead of addressing those issues directly, “Transamerica” opts for a close examination of the psyche, mind, and soul and of one transsexual.

Stanley/Sabrina, or Bree (Felicity Huffman) as he/she goes by, is in the process of transforming from a man to a woman. One operation, involving the change from penis to vagina, is the final procedure left before completely and officially becoming a woman. “Transamerica” is the story of Bree, a conservative transsexual who takes an unexpected journey when she learns that at college she had fathered a son, Toby (Kevin Zegers), now a teenage runaway hustling on the streets of New York City.

A pre-op transsexual, Bree has had electrolysis, facial feminization surgery, years of hormone therapy, everything but the final genital operation. Her life had been incredibly difficult, struggling constantly with loneliness, the pain of her past, and uncertain future. More than anything else, Bree desires “a normal life,” but it's never clear whether her dream would remain beyond her grasp.

A highly educated transsexual, who passes as a G.G. (a genetic girl), Bree lives in a poor section of Los Angeles, working two jobs to save money for her final reassignment surgery. When she receives a phone call from Toby, a jailed teenage runaway looking for his father, she's shocked to discover that a heterosexual encounter during her college life as a man had resulted in having a son.

When Bree tells her psychiatrist Margaret (Elizabeth Pena) about the call, the latter withholds her signature on the surgical form and suggests that Bree go to New York to meet with her son. Decidedly not thrilled with this turn of events, Bree wants no part of Toby, but her therapist insists she must confront her past. Grudgingly dipping into her precious operation fund, Bree flies to New York to bail Toby out of jail.

Released to her without explanation, Toby assumes from Bree's conservative appearance that she's a Christian missionary who rescues street people and converts them to Jesus. For her part, not ready for parenthood, Bree seizes her chance and encourages Toby's misconception. When she learns that the rebellious Toby intends to skip bail and hitchhike to L.A. to break into X-rated videos and search for his real father, Bree panics. She doesn't want him to interfere with her plans for a safer, quieter new life.

Nonetheless, a sense of responsibility takes hold of Bree, and she offers Toby a cross-country ride, secretly plotting to abandon him with the stepfather he ran away from. During the journey, Bree maintains her “deep stealth” (living as a genetic female), keeping two secrets from Toby, her biological history and his.

The cross-country drive enables them to get to know each other, though Bree never discloses her true identity. As each lies to and manipulates the other, Bree and Toby find themselves on an unexpectedly transformative journey, hence the film's title. Unfolding as a road movie, the movie places two extraordinary characters against a backdrop of ordinary Americans. Bree and Toby unwittingly pioneer new territory in their own lives as they travel from the Northeast to the Southwest. The sweep and scope of the landscape they pass through reflect their interior journeys.

Toby comes across as a street hustler who's damaged and guarded. Confusing sex with affection, he believes that physical appeal is the only measure of his worth. Suffering from terrible self-image problems, Toby toys with dangerous drugs, finding it difficult to relate to adults in a non-sexual way. He's angry, suspicious, eager-to-please, hungry for attention, seductive, and highly sexual. This is why Toby comes to Bree's bed–out of empathy and loneliness he tries to give her the only gift he thinks he can offer–in a scene that's meant to make the viewers uncomfortable since it borders on incest.

As Dr. Spikowsky tells Bree early on, Gender Dysphoria (aka Gender Identity Disorder, or GID) is listed in the Diagnostic and Statistical Manual of Mental Disorders endorsed by the American Psychiatric Association. This listing has had the dual effect of giving transsexualism legitimacy, since there's a medical diagnosis for it, but also of stigmatizing transsexuals as mentally ill. “Transamerica” conveys the message that while transsexuality is not a mental disorder, living as transsexuals in a society that shuns transsexuality causes great emotional distress.

As characters, Toby and Bree could not have been more different. She is conservative, verbal, and extremely body conscious. He is wild, exhibitionistic, and insecure. As loners living in a world that has abused and stigmatized them, both have retreated and closed themselves off. The core of their revelatory journey resides in the tensions that prevail between their differences and similarities and the compromises both are forced to make.

In moments, the journey is funny and marked by a lively sense of adventure and of possibility. Instead of settling into a quirky odd-couple story, the film is full of unexpected turns, with every character the duo encounters along the road well observed, including a free-spirited hitcher (Grant Monohon) and a New Mexico rancher (Graham Greene) who gallantly comes to Bree's assistance. David Mansfield's Americana-tinged score underlines the optimistic, pessimistic, and plaintive notes of a journey.

Tucker's script and direction weave humor into his characters' longing for acceptance, particularly when their journey takes them to the Phoenix Mansion of Bree's family. Bree's parents (Fionnula Flanagan and Burt Young) and sister (Carrie Preston) have been feeding her self-doubt. But even the monstrously materialistic mother reveals a human side to her.

The locations, the high desert outside of Chino Valley, Watson Lake in the Granite Dells, a beautiful ranch in the boulders outside of Prescott, white bluffs in Skull Valley on the old Senator Highway. Bree's and Toby's “honeymoon scene,” and the scenes leading up to the film's conclusion, in which Toby discovers Bree's true identity, required Huffman and Zegers to create an honest and complex dynamics between them. The transgender spin avoids gimmickry thanks to Tucker's deft touch and the subtle work of Huffman and Kevin Zegers as the lost-and-found offspring.

On the big screen, “Desperate Housewives” star Huffman has been relegated to secondary roles, but with “Transamerica,” she steps into a challenging lead role with an extraordinary portrait. Huffman gives a riveting performance as Bree/Stanley, for which she won the Best Actress Award at the Tribecca Film Festival. She captures all the contradictory feelings of her character: The unappeasable anger, the great resilience, the beauty of spirit. Huffman embodies the complex layers of self-awareness and denial in a prim yet courageous individual, who each day must paint on a face and put on a voice to become her more desirable self.

As a boy who considers sex his chief talent, Kevin Zegers (“Air Bud,” “Dawn of the Dead” remake) conveys Toby's essential goodness and hunger for real affection, making him much more than just a vain, damaged, or abused kid.

Tucker's character-driven script contains a few plot elements that strain logic, but the dialogue sounds realistic enough for us to fee empathy for Bree's predicament. Forcing viewers to look at a phenomenon they don't know much about, the film tries to overcome people's biases against transsexuals by showing their humanity and decency. Rather than feel “sorry for” or “fear of” someone who is different, “Transamerica” preaches for greater understanding and compassion for gender and cultural diversity.

For better or worse (I think the latter), gender politics is an element of “Transamerica” but not its subject. Tucker's main concerns are loneliness, emotional honesty, and the need for human kindness.