Conservative groups in the US have instigated a protest campaign against Bill Condon's adept, sexually frank biopic Kinsey, which is shaping up as a strong Oscar contender.

Liam Neeson is hotly tipped to collect a Best Actor nomination for his vibrant and authoritative portrayal of the pioneering American sexologist Alfred Kinsey. The film came under attack when it opened on limited early release in the US last weekend.

Generation Life, a college group, said it would picket cinemas showing the film and hand out anti-Kinsey pamphlets. Its leader, Brandi Swindell, said her goal is to discourage audiences from attending the film, at least until they do their own research. She accused Kinsey of "sugarcoating the issue," saying there would be more negative information about Kinsey's legacy "if it were a true documentary", even though the film does not purport to be a documentary. The director of Concerned Women for America's Culture and Family Institute went so far as to compare Kinsey to Dr Josef Mengele or "your average Hollywood horror-flick mad scientist".

Nancy Utley, marketing president at Fox Searchlight Pictures, noted parallels with the protests Kinsey faced, quoting one of his lines in the movie: "The forces of chastity are amassing once again." Director Condon said the film's US release would "start in the blue state cities and go from there". Neeson added: "Kinsey did release the genie from the bottle - and you can't put the genie back in the bottle." Nice work if you can get it.