(CNN) Sam Clovis, Donald Trump's pick to be chief scientist for the Department of Agriculture, has argued that homosexuality is a choice and that the sanctioning of same-sex marriage could lead to the legalization of pedophilia, a CNN KFile review of Clovis' writings, radio broadcasts, and speeches has found.

Clovis made the comments between 2012 and 2014 in his capacity as a talk radio host, political activist, and briefly as a candidate for US Senate in Iowa. His nomination has drawn criticism from Senate Democrats, who argue his lack of scientific background makes him unqualified for the USDA post overseeing science.

Clovis has repeatedly argued that the science on homosexuality is unsettled and that "LGBT behavior" is a choice. The American Psychological Association has said that while there is no scientific consensus on the causes of sexual orientation, "most people experience little or no sense of choice about their sexual orientation."

Asked for comment on Clovis' beliefs surrounding the science of homosexuality, a USDA spokeswoman told CNN: "The Supreme Court settled the issue in 2015." The White House did not respond to a request for comment.

KFile has previously reported on controversial comments Clovis made during his time as a talk radio host about race and then-President Barack Obama. At that time, a USDA spokesperson said that Secretary of Agriculture Sonny Perdue still supports Clovis to be the under secretary for research, education and economics.

Clovis, whose background and views are strongly rooted in the politics of conservative talk radio, made most of his remarks in the context of discussing his belief LGBT people should not be given protections under the 14th Amendment to the Constitution. He says he believed that if LGBT people got such protections, pastors wouldn't be allowed to preach against the "aberration" that "alternative lifestyles" were to church doctrine.

Writing in an op-ed for the local conservative blog Iowa Republican in April 2011, Clovis argued science of being LGBT was unsettled and if being gay was genetic, then other people genetically-disposed like left-handed people should receive constitutional protections as well.

"Today, there are six protected classes of American citizens who benefit from the history of legal precedents associated with American traditions and the 14th Amendment. Two of these classes—religion and military—have long been established in the traditions of the nation. The other four—race, gender, disability and age—are based on primary characteristics. Primary characteristics are those human features we can generally discern by visual examination—something we can see. Following this logic, the only way to extend 14th Amendment protections to those in the LGBT lifestyles is if these behaviors are genetically mapped or otherwise discernible. The science on this issue seems to be uncertain, and if one followed the arguments from plaintiffs, the issue argued was that these individuals, because of 'love,' should be allowed to 'marry just like opposite-sex couples.' What is it really? Is this about genetics or about emotions? The stronger case is genetics, but that is not the argument being advanced. If LGBT adherents were genetically predisposed, then one must ask why a segment of the population that constitutes numbers less than one third of those who might be left-handed or one fourth the number who might be blue-eyed or one eighth the number who might be genetically predisposed to obesity should receive 14th Amendment protections when others are not even considered. Certainly left-handers have more to bark about than most. Thus, the argument must be about something other than genetic predisposition."

At a campaign stop during his failed campaign for the Republican Senate nomination in Iowa, Clovis said the science was still out but "as far as we know" being LGBT is choice. Clovis then concludes the protecting of LGBT people could mean that pedophilia would also be protected.

"Someone who engages in LGBT behavior -- I don't know what the science is on this, I think it's still out -- but as far as we know, LGBT behavior is a choice they make, Clovis says in a video obtained by CNN's KFile. "So we're being asked to provide Constitutional protections for behavior, a choice in behavior as opposed to a primary characteristic."

"There's no equivalency there between the civil rights issue associated between those protected classes and the civil rights of someone who engages in a particular behavior," continues Clovis. "Follow the logic, if you engage in a particular behavior, what also becomes protected? If we protect LGBT behavior, what other behaviors are we going to protect? Are we going to protect pedophilia? Are we going to protect polyamorous marriage relationships? Are we going to protect people who have fetishes? What's the logical extension of this? It can't be that we're going to protect LGBT and then we'll pull up the ladder. That's not going to happen, it defies logic. We're not thinking the consequences of these decisions through."

When a questioner said some might call what Clovis' words extreme -- comparing the approval of same-sex protections to allowing pedophilia. Clovis said it was "logical."

"I don't think it's extreme," said Clovis. "I think it's a logical extension of thought. And if you cannot follow the logic then you're denying your in denial."

Clovis also expressed his belief the LGBT community itself wanted more than same-sex marriage protected. Writing on his blog in May 2012, the day after then-President Obama announced he supported same-sex marriage, Clovis said the LGBT community might not stop at same-sex marriage but posited that they could move on to "polyamorous arrangements."

"In America, there has been strong support in our legal system to define marriage as between one man and one woman," Clovis wrote. "In particular, the Supreme Court as far back as the 1870s established that very definition of marriage. What seems the most troubling about extending the definition of marriage to same-sex couples is that it will be difficult to stop with this revised definition.

"Is the LGBT community wanting to stop the marriage arrangement at any two consenting adults? This is illogical. If society chooses to alter the definition of marriage, how can there be a line drawn at two adults? What is to say that polyamorous arrangements should not be included? What about other relationships? If that is the goal of the LGBT community leadership, then the reasons for rearranging the traditional definition is far more nefarious than just making a small segment of the population feel better."

In the same blog post, Clovis said religious freedom meant business should be able to not hire LGBT people if it conflicted with their religious belief.

"Homosexuality and personal choices about one's sexual preferences is not at issue. Businesses today have extended support to life partners in a number of ways. It's just good business if that is what it takes to get the best person for the job," added Clovis."On the other hand, businesses and their owners should be able to make decisions about who is employed if hiring people who do not behave in accordance with some deeply held religious belief system is at issue. Just as the government should not force business owners or enterprises to provide contraceptives or morning-after pills because of religious beliefs, the government should not be in charge of hiring practices, either. Religious freedom, perhaps the most fundamental of all protected freedoms, must be free of government interference."