CNN's KFile reviewed several months of audio from Rep. Jason Lewis on the "Jason Lewis Show," a syndicated radio program Lewis hosted from 2009 until 2014 with the tagline "America's Mr. Right." In one instance, while arguing that "young single women" vote based on coverage of birth control pills, Lewis said those women were not human beings and were without brains.

Lewis, who was narrowly elected to represent Minnesota's 2nd District in 2016, is considered one of the most endangered House Republicans in the midterm election. CNN rates the race as a "toss up," the most competitive designation.

Lewis can be heard on the radio repeatedly demeaning women, and particularly women voters, in 15 months of audio provided to KFile by Michael Brodkorb, the former deputy chair of the Republican Party of Minnesota. Brodkorb, who is currently a columnist for the MinnPost and works in public affairs, initially revealed some of Lewis' radio comments in a column in February 2016 . KFile contacted Brodkorb after seeing his 2016 column and requested raw audio files of Lewis' show, which he provided.

When radio host Rush Limbaugh called women's rights activists and then-graduate student Sandra Fluke "a slut" in February 2012, Lewis repeatedly expressed disbelief that people could no longer refer to women as sluts.

"Well, the thing is, can we call anybody a slut? This is what begs the question. Take this woman out of it, take Rush out of it for a moment," Lewis said in a March 2012 episode. "Does a woman now have the right to behave -- and I know there's a double standard between the way men chase women and running and running around -- you know, I'm not going to get there, but you know what I'm talking about. But it used to be that women were held to a little bit of a higher standard. We required modesty from women. Now, are we beyond those days where a woman can behave as a slut, but you can't call her a slut?"

Fluke, a law student at Georgetown at the time, found herself at the center of a national controversy in early 2012 after Limbaugh attacked her following her testimony to a Democratic congressional group. In her testimony, Fluke said that students paid as much as $1,000 a year for contraceptives and made the case that religious institutions should cover birth control. She said she was "stunned" and "outraged" by Limbaugh's remarks.

Lewis, who was a regular fill-in for Limbaugh's national radio show, also offered a defense of the right-wing radio host for his comments on Fluke, saying, "Now Limbaugh's reasoning was, look, if you're demanding that the taxpayers pay for your contraception, you must use a lot of them and therefore, ergo, you're very sexually active and in the old days, what we used to call people who were in college or even graduate school who were sexually active, we called them sluts."

He continued, "Especially if you want somebody to pay for it. Now you know, obviously that's a stretch. It was meant as an aspect of entertainment radio."

He continued, "But have we really got to the point where you can't refer to Madonna as a slut without being sued? I mean, Madonna has had a series of lovers, as have many in Hollywood. Now in the old days, what did we call this? Madonna dresses up in these sorts of prostitute-like outfits on stage, and she goes there and she sings and she shows half of her body. What did we call those people? 30 years ago? 40 years ago? 50 years ago? You can't do that today, it's too politically incorrect?"

Lewis, during a December 2012 segment on changes in the culture, said, "Only we can tell our young women, 'don't look like some slut and you won't get hit on.'"

In a statement, Lewis' campaign defended his comments.

"This has all been litigated before, and as Congressman Lewis has said time and time again, it was his job to be provocative while on the radio," Lewis' campaign manager Becky Alery said in a statement.

Lewis' time as a radio show host initially came under scrutiny during the 2016 campaign. In addition to Brodkorb's column, The Atlantic magazine dubbed Lewis Minnesota's "Mini Trump" in an article that reviewed a sampling of comments he made about women and minorities, including a comment in which he called young female voters "ignorant of the important issues in life" who needed to be educated.

Lewis' shocking comments from his show flew under the radar at the time, and some of his most inflammatory comments about women, including his views on the term "slut," were never previously reported. Minnesota Democrats called on Lewis to release his full radio show archive, but he dismissed their demands a "distraction" and claimed his comments would be taken "out of context."

Echoing comments reported by Brodkorb and The Atlantic, Lewis on several more occasions described women voters as guided by emotion instead of reason and said they voted solely on the issue of free birth control. Lewis at times seemingly confused the kinds of birth control covered by health insurance policies.

On an August 2012 show, Lewis speculated that then-President Barack Obama led with women because of this.

"To the degree that the Republicans or conservatives or Mitt Romney has an issue with the women, maybe it isn't Mitt Romney or his positions. Maybe it's the women," Lewis said. "We all know that women tend to vote more liberal than men. It is the women who are guided by more emotion than reason. 'Oh, here we go, stereotyping, stereotyping females once again. What are you doing?' Well, I'm not running for anything. I'm just making an observation."

He added, "One of the reasons that the Democrats love the quote unquote female issue is because they know women vote more liberally than men do. Now you could say in a very, very sexist, misogynistic way that, 'well, that's because women just don't understand money. They don't understand, they're, they don't handle finances. They're guided by emotion not reason. Why, that's why they didn't have the vote for a full century in the country.' Well, it is true that women cast more votes for Democrats. All I'm saying, I'm not validating the stereotype. I'm married to a woman for heaven's sakes, but I will say this: Do not, do not pander and move left to get the female vote."

In a November 2012 broadcast, Lewis said women, by voting for Democrats, played into the stereotype that they don't think.

"So there is something here going on with women who are playing into that stereotype that they're not thinking," he said. "Oh, 'I know that's awfully prejudicial because the only way you can think is it a vote Republican, Jason.' I'm not saying voting Republican, but when you reliably almost a knee-jerk Democrat vote -- is birth control really that important to you ladies? Is that really the most important thing that you get your condoms for free? Now you've gotten Madonna, you know, running around and slutty outfits and Sandra Fluke telling everybody I'm not going to pay a dime for my diaphragm. Is that really what's important to women? I can't believe that. And yet there's this gender gap every election cycle. Women go Democrat."

The next day, Lewis argued that "young single women" who voted based on coverage of birth control pills had ceased to be human beings.

"You can be bought off for that?" he said. "I mean, boy, that's the, all the other issues: the Hispanic problem, social issues, class warfare, you know, we can figure out a way to tackle those. This one, if you're that far down the road and you say you're a human being, I've got my suspicions. You're not, you're without a brain. You have no, you have no cognitive function whatsoever. If that's all it takes to buy you off."

Representatives for Madonna did not return a request for comment.

In a statement to CNN, Fluke said, "Jason Lewis' attitude toward the women of his district and this country is incredibly insulting and beneath any member of the United States Congress. Americans stood with me and resoundingly rejected such uncivil and demeaning attacks from public figures back in 2012. Since then, the brave women of the #MeToo movement have again reminded all of us that disparaging women with insults like 'slut" and "parasite,' is an attempt to silence them from speaking up and fighting for comprehensive healthcare they can afford."