KINSEY: Written and directed by Bill Condon. Produced by Gail Mutrux. Executive producers Michael Kuhn, Francis Ford Coppola. Bobby Rock, Kirk D’Amico. Cinematography, Frederick Elmes. Production design, Richard Sherman. Editor, Virginia Katz. Costume design, Bruce Finlayson. Music by Carter Burwell. Starring Liam Neeson, Laura Linney. With Chris O’Donnell, Peter Sarsgaard, Timothy Hutton, John Lithgow, Tim Curry, Oliver Platt, Lynn Redgrave and Dylan Baker. Fox Searchlight Films, 2004. R. 118 minutes.

Last Sunday, I found myself thinking about sex. First I read a Washington Post story by a health and human sexuality educator of 30 years. Deborah Hoffman said teaching about sex should educate, not dictate, and that it should be “based on scientific evidence.” Later I saw Kinsey, an artfully done cinematic biography of the world’s first scientist to actually study adult human sexual behavior. Were Alfred Kinsey alive today in the midst of a culture-war waged by the religious right against science, I have no doubt he would fully support Hoffman’s recommendations.

No traditional biopic, Kinsey opens on a face-to-face training session between Kinsey (Liam Neeson) and his three research assistants, Clyde Martin (Peter Sarsgaard), Wardell Pomeroy (Chris O’Donnell) and Paul Gebhard (Timothy Hutton). In turn, each interviewer questions Kinsey about his sexual history and records his answers in code. Kinsey helps them achieve an open attitude toward sex, keep an interested but not judging demeanor, and use frank, non-euphemistic words about sexual behavior appropriate to the person’s background — penis for well-educated subjects, he suggests, but prick, dick or other slang for the less educated.

Neeson’s gifted, down-to-earth portrayal is astonishing, from his wispy hair to his bemused twinkling eyes. A nature-loving, serious scientist, Kinsey spent his first 20 years of academic life capturing a million specimens of the gall wasp and the remaining years asking just such candid questions of adult American men and women in the 1940s and ’50s.

Kinsey’s 1948 Sexual Behavior in the Human Male sold out its first printing in mere days. His research showed that between 67 percent and 98 percent of men had sex before they were married. Fifty percent had extramarital affairs, a whopping 92 percent masturbated, and 37 percent had had at least one homosexual experience.

Kinsey’s 1953 Sexual Behavior in the Human Female showed that 50 percent of women had premarital sex, 26 percent had extramarital sex and 62 percent masturbated. Feminists will not be surprised to learn that this book was received with shock and awe by the patriarchy, nor that Kinsey became a cultural untouchable as a result of publishing his findings.

The movie is about Kinsey’s life, not only his work. His wife and former student, Clara McMillen (Laura Linney), is as brilliant, open-minded and adaptable as he is. Linney plays Mac, as she was called, with a delicate humor that almost belies the depth of her performance. She models for us the way such a woman married to a famous man might find to keep her own life alive, while supporting him in the most important ways. The Kinsey’s dinner conversations with their young adult children is absolutely hilarious. Mealtime with my family was nothing like this.

Sarsgaard’s portrayal of Kinsey’s assistant Martin is as nuanced as I have come to expect from him and as luminous as Linney’s. Considered a member of the family, Martin’s frequently found at the Kinsey home. He develops a special bond with both Albert and Clara.

We come to see Kinsey through the eyes of Clara and Martin, whose love for him enables us to see his almost-innocence, personal grief and manipulation. Kinsey is damaged goods, but love helps him find a redemption his work alone could not.

Kinsey’s two great achievements are that he found a way to get people to open up about their sexuality without shame and guilt, and that he used the data he collected to show there is no such thing as “normal” sexual behavior. As he noted about gall wasps more than a half-century ago, no two individuals are alike: “There is only variation.” His portrait of American sexuality at mid-20th century was followed by Masters and Johnson’s Human Sexual Response, 1966, which has had an equally liberating effect on the lives of adult men and women. But Kinsey was the first.

Kinsey opens at the Bijou Saturday, Dec. 25, with my very highest recommendations. One of 2004’s best pictures.