David Liu from Harvard University questioned He on the unmet medical need of the experiment. Liu said an HIV-positive father and an HIV-negative mother already have a high possibility of having an HIV-free baby after "sperm washing", an effective technique that separates sperm from infected cells before fertilization to ensure the virus isn't transmitted. During the talk, He said he had performed the procedure in the experiment.

Some scientists also voiced concerns over the backlash of He's experiment on gene editing technologies worldwide.

"I feel more disturbed now," said Liu, who is also associated with MIT's Broad Institute and is the inventor of a variation of the gene editing tool. "It's an appalling example of what not to do about a promising technology that has great potential to benefit society. I hope it never happens again," he was quoted as saying by the Associated Press on Wednesday.

George Daley, dean of Harvard Medical School and one of the conference organizers, said that because the case might have been a misstep, it "should in no way, I think, lead us to stick our heads in the sand and not consider the very, very positive aspects that could come forth by a more responsible pathway".