America’s carnal knowledge has expanded, to put it mildly, in the years since Dr. Alfred Kinsey (1894-1956) published his ground-breaking books “Sexual Behavior in the Human Male” (1948) and “Sexual Behavior in the Human Female” (1953).

But the new film biopic “Kinsey,” which opens Friday, makes it clear it was the controversial zoologist who “got the national conversation about sex started,” says the film’s writer-director Bill Condon.

“That’s why he’s still a lightning rod to this day,” Condon adds. “He was an early feminist, though some feminists later took issue with him. He was an influence on the gay movement, and there’s a direct line from his work to the sexual revolution of the ’60s. I’m not sure if we’d have gotten to where we are now without him.”

In the movie, Kinsey (Liam Neeson), his wife, Clara (Laura Linney), and his assistants interview people about their private sexual practices in a pioneering face-to-face style, then catalog and assess them. The language Kinsey used could be a dictionary of terms for scores of sex columnists, Howard Stern and “Sex & the City.”

Linney says Kinsey’s intention would even be appreciated by today’s moral majority.

“People now get wrapped up in Kinsey’s controversy and his bisexuality, but he initially started all of his research to benefit the institution of marriage,” she explains. “He knew for a marriage to be successful, the sexual relations have to be solid. At Indiana University, he taught his findings in a marriage course. He was a firm believer in the family. People tend to glide over that.

“America has such a schizophrenic relationship with sex,” Linney continues. “It’s been over 50 years since Kinsey, and like him or not, he changed our culture and how we’re educated about this aspect of ourselves.”

There is a current reexamination of what Kinsey’s studies mean to the modern world. Condon’s film, several recent biographies, and T.C. Boyle’s just-published novel, “The Inner Circle,” all examine Kinsey’s life and work.

“Kinsey opened sex up so people could talk about it, the press could write about it, cartoons could be made about it, and songs could be sung about it,” says Boyle. “He said, ‘It’s science, we should know about it.’ And that frank medical text was a best-seller, at the time, second only to ‘Gone with the Wind.’ People wanted to know, and people still want to know.

“My book allows a reader to be a step ahead of Kinsey. Yet even today, no matter how sophisticated we are or what’s available on the Internet, there still exists the idea of your first sexual experience. And in a cultural sense, that was Kinsey.”

“I do wonder why there’s a ‘Kinsey moment’ right now,” says feminist critic and author Katie Roiphe. “Perhaps we’re aware of crises in marriages. It could be fallout from the sexual revolution. Or maybe it’s our conservative political time, when, just as in the 1950s, there are many things going on beneath the surface.

“It’s part of our Puritanical legacy to believe there are dark sexual secrets lurking behind every door, so when something like a ‘Kinsey Report’ comes out, it plays into all of our fantasies, fears and anxieties.”

“We owe Kinsey a lot for [enabling] broad-brush, inclusive studies of what people do,” says the University of Chicago’s Ed Laumann, co-editor of “The Social Organization of Sexuality: Sexual Practices in the United States.” “But he was eventually defunded, and no one picked up on his work until [William H.] Masters and [Virginia E.] Johnson in the ’60s. I think the opening up of people to these concerns [reflects] growing options and exposure.”

For all the hue and cry over various hot-button issues, the American skin has grown thicker when it comes to being shocked by sex.

“For a report to have a similar kind of effect now, the revelations would have to be in the opposite direction – like, if young people stopped having premarital sex. Today, that would be the only thing that could be shocking,” Roiphe says.

“There are a million reports now that say this or that about sex, and we don’t pay any attention to them in the same way we did in 1948,” she concludes. “And that’s because our whole media has now become like one big ‘Kinsey Report.’ In a sense, Kinsey is everywhere.”