A documentary about the travails of the transgendered risks sealing itself into a bubble of sad compassion, and when that film has won the Grand Jury Prize at Sundance, a viewer has every right to be wary: Too often, this award has been turned into a kind of Nobel PC Prize. But Kate Davis' lovely and moving Southern Comfort melts all wariness away. Set in the backwoods of Georgia, it offers a memorable portrait of Robert Eads, who was born a woman, got married and raised two sons, and then ''transitioned'' into the man we see: a sinewy, pipe-smoking cowboy with a wispy beard and the courtliest of Southern manners.
Robert's lover, the tall, demure Lola, is a transsexual herself, and the movie, for a while, indulges the delectable irony of this topsy-turvy gender union. Yet it goes deeper than that. Robert, a brave-new-world pioneer who is also a down-home traditionalist, has ovarian cancer, and as he confronts his mortality in a society where many physicians refuse to treat him, the film defuses all preconceptions about the ''issues'' of transsexual identity to arrive at a place of tremulous human power.