FIRST ON FOX: The GOP Doctors Caucus sent a letter to White House chief medical adviser Anthony Fauci demanding he apologize for calling Sen. Roger Marshall, R-Kan., a "moron."

GOP Doctors Caucus vice chair Rep. Greg Murphy of North Carolina led the physicians' letter to Fauci, blasting President Biden’s top medical aide for his lack of professionalism toward the Kansas senator.

"Dr. Fauci has forfeited his credibility as a public health expert by placing political science ahead of medical science," Murphy, a practicing surgeon, told Fox News Digital in a Tuesday statement. "Physicians have an obligation to put forward clear, consistent, and well-educated messaging to inform patients and the public. Instead of fulfilling this responsibility, Dr. Fauci has administered confusing and conflicting information in an air of arrogance that has resulted in a marked decrease in the public’s trust."

SENATOR PUBLISHES FAUCI’S UNREDACTED FINANCIAL DISCLOSURES, ACCUSES HIM OF BEING MISLEADING

"Dr. Fauci’s recent denigrating antics in undermining our highly respected colleague, Dr. Marshall, is just the latest example of his tragic failure to lead," the North Carolina Republican continued. "We ask that Dr. Fauci make a public statement immediately withdrawing his derogatory comments, and reflect on the fact that medical opinions are best achieved through consensus and humility, not arrogant monolithic statements. Dr. Fauci should take stock of how his divisive actions have done our nation more harm than good."

Rep. Greg Murphy, R-N.C., walks down the House steps after a vote in the Capitol on Tuesday, Sept. 15, 2020. (Photo By Bill Clark/CQ-Roll Call, Inc via Getty Images)

Rep. Greg Murphy, R-N.C., walks down the House steps after a vote in the Capitol on Tuesday, Sept. 15, 2020.  (Bill Clark/CQ-Roll Call, Inc via Getty Images)

The lawmakers wrote that, while "certain medical disease states lend themselves easily to physician consensus," the country has seen "anything but" during the COVID-19 pandemic.

"We have seen unfortunate deprecation by some physicians to other physicians over disagreements in issues dealing with masks, therapeutics as well as vaccines," the letter exclusively obtained by Fox News Digital reads.

"People expect physicians to be tolerant and always respect diversity," the lawmakers continue. "A physician, especially in a national leadership position, who doesn’t respect diversity – which includes diversity of opinion – reflects poorly on our entire profession."

The Republicans wrote they "understand that congressional hearings can sometimes be challenging" and lambasted Fauci’s "behavior" of calling Marshall, a fellow medical doctor, a "moron" during a Senate hearing as "extremely unprofessional and uncalled for."

Sen. Roger Marshall, R-Kan., departs a meeting at the U.S. Capitol in Washington, D.C., Dec. 1, 2021. (REUTERS/Elizabeth Frantz)

They noted that Marshall "is a highly qualified physician and highly respected" and that physician "colleagues, even when they do not agree, should not stoop to calling another colleague a juvenile name."

"The medical profession is one that is normally held in high esteem. This type of behavior undermines the trust that Americans have in physicians," the elected doctors wrote, calling on Fauci to publicly apologize to Marshall for his "unprofessional comment."

Joining Murphy on the letter are 13 of his fellow GOP physician colleagues, including Reps. Brad Wenstrup of Ohio, Mariannette Miller-Meeks of Iowa, and Brian Babin of Texas.

Fauci’s vituperative hot mic comment toward Marshall spurred from their sparring over the public availability of Biden’s top medical adviser’s financial disclosures and ignited a firestorm among Republicans.

Marshall was not one to take the treatment sitting down, publishing Fauci's latest financial disclosure -- which had not been published yet.

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While Fauci's financial disclosures are technically open to any member of the public who requests them, the records are not listed in an easily-accessible public database, and it can take months for a request to be fulfilled.

The National Institute of Allergies and Infectious Diseases (NIAID) did not immediately respond to Fox News Digital’s request for comment.