At the time and repeatedly since, he has denied that the research constituted what's known as 'gain-of-function' research. Gain-of-function research is the scientific term given to research that deliberately changes an organism to make give it new functions in order to test a theory. Dr. Fauci insisted to Congress in May that the US has never funded any kind of gain-of-function research in Wuhan to do with COVID-19. This is what Fauci refers to when he insists the US never funded any kind of gain-of-function research. His critics say that what the Wuhan scientists were doing was just that, and the US is not admitting it.

Source: Daily Mail September 07, 2021 19:18 UTC