If "The Sessions" wasn't based on a true story, it would be one of the strangest premises to be put on celluloid. A severely disabled man hires a sex surrogate after he gets permission from his priest to lose his virginity.

"I know in my heart that God will give you a free pass on this one. Go for it," Father Brendan tells Mark O'Brien, a quadriplegic who, after suffering a bout of polio as a young boy, spends much of his time in an iron lung.

Director Ben Lewin got the idea for the movie after stumbling upon writer/poet O'Brien's 1990 article "On Seeing a Sex Surrogate," which was published in a literary magazine. Set in Berkeley, Calif., in 1988, the movie centers on O'Brien's decision at the age of 38, to experience sex. But this is no "40-Year-Old Virgin" film. While treated with comedy and wit, the subject matter is taken very seriously.

O'Brien is played by John Hawkes ("Winter's Bone," "Lincoln") who approaches the character with precisely the right amount of cynicism and perseverance, leaving behind any of the drama that usually goes with playing a disabled person. Hawkes researched the character by speaking with the people who were close to O'Brien (he died in 1999 at the age of 49). Then, Hawkes decided to make this portrayal even more real by enduring some serious physical pain. He wore something called a "Torture Ball" during rehearsals and the movie shoot to help curve his spine and contort his body. His performance is as genuine as it gets. Definitely an Oscar nomination for Hawkes for this role.

Helen Hunt plays sex surrogate Cheryl Cohen Greene. The real life therapist is a grandmother and still practicing her craft in Massachusetts (in some states, sex surrogates are illegal). Hunt's performance would have been flawless, except for her the spotty Boston accent, which is nothing short of annoying. If you can get past it, she plays Greene with a stern sensibility and gentle compassion. Greene takes her job seriously. She's not a prostitute, she softly explains to O'Brien. There are wonderful scenes of Hunt as Greene alone at the end of the night, speaking in to a tape recorder, dictating the progress she is making with her client. It's small moments like these in the film that are captivating.

Adam Arkin plays Greene's understanding husband whose jealousy bubbles up when the "professional" relationship she has with her client appears to be crossing the line. Unfortunately, Arkin's character is one of two that is underdeveloped and underused (the other is O'Brien's eventual life partner Susan Fernbach, who is introduced briefly almost near the end of the film), but there's a lot to cram into 95 minutes.

One of the most delightful performances, in addition to Hawkes, is the actress with a most unusual name, Moon Bloodgood, who plays O'Brien's caregiver. Television fans may recognize her from her role on the TNT cable network's show "Falling Skies." As Vera, she falls somewhere perfectly in the middle of Hawkes' wry O'Brien and Hunt's sympathetic Greene.

William H. Macy pops in and out as Father Brendan, O'Brien's confidante. The character is actually a conglomeration of many priests that the practicing Catholic sought out for advice. Macy finds the human side of the man of the cloth, playing him as a free-wheeling, beer-drinking pastor who believes God gives "free passes" in certain situations.

There's a no holds barred appeal that gives "The Sessions" its stamina. Writer-director Ben Lewin had contracted polio himself as a child and this layer of insight comes through and the filmmaker keeps the subject matter light. Yes, this is a movie that concentrates entirely on sex, but it's also about basic human needs, and that's something very relatable.