National Institute of Allergies and Infectious Diseases (NIAID) director Dr. Anthony Fauci wrote in 2012 that pathogenic gain-of-function research was worth the risk of a potential man-made pandemic.

In a paper from 2012, Fauci defended controversial gain-of-function research, saying that the "benefits" gained from the science "outweigh the risk" of an accidental pandemic breaking out.

In a controlled lab setting, gain-of-function research increases the deadliness and transmissibility of viruses so scientists can better understand how pathogens mutate and replicate. Researchers can then use that information to develop more effective vaccines. 

The research is used to stay ahead of the curve of potential new diseases and to develop new treatments and vaccines, but it can carry a risk of outbreak if not conducted safely.

FAUCI DEFENDS ‘MODEST’ COLLABORATION WITH WUHAN SCIENTISTS, SAYS NIH DIDN’T FUND ‘GAIN OF FUNCTION’ RESEARCH

"It is more likely that a pandemic would occur in nature, and the need to stay ahead of such a threat is a primary reason for performing an experiment that might appear to be risky," the paper reads.

Fauci wrote that the scientific community needed to "respect that there are genuine and legitimate concerns about this type of research," such as a pandemic beginning with less-experienced, less-funded scientists becoming infected and spreading the disease under research.

"Those of us in the scientific community who believe in the merits of this work have the responsibility to address these concerns thoughtfully and respectfully," the NIAID director wrote.

Fauci did not immediately respond to Fox News’ request for comment.

The Australian first reported on Fauci's previous paper on Friday.

CLICK HERE TO GET THE FOX NEWS APP

On Tuesday, the NIAID director defended the "modest" collaboration between the Wuhan Institute of Virology (WIV) and NIAID to study bat-transmitted coronaviruses but denied the money went to gain-of-function research.

Six-hundred thousand dollars from NIAID was given to a group called EcoHealth Alliance, which, in turn, paid the WIV to study the risk of bat coronaviruses infecting humans.

"I would have been almost a dereliction of our duty if we didn't study this, and the only way you can study these things is you've got to go where the action is," Fauci said, referencing the early-2000s SARS outbreak, which is presumed to have come from bats.

Fox News’ Tyler Olson contributed to this report.