He Jiankui speaking during the Human Genome Editing Conference in Hong Kong, Nov 2018.

Chinese biophysicist He Jiankui sparked a global uproar last year, when he announced that he had created the first gene-edited babies.Credit: Kin Cheung/AP/Shutterstock

Stanford University has cleared three of its faculty members of any wrongdoing related to their interactions with He Jiankui, the biophysicist who created the first gene-edited babies.

The researchers, whom Stanford did not name, “had no research, financial or organizational ties” to the gene-edited-baby scandal, the university said in a statement on 16 April. A Stanford investigation found that the researchers tried to discourage He from following through with his controversial experiments, which prompted a global outcry.

At the time, He was working at the Southern University of Science and Technology in Shenzhen, China. His relationships with the Stanford researchers date back to 2011, when he performed postdoctoral research at the California university.

“When Dr. He did not heed their recommendations and proceeded, Stanford researchers urged him to follow proper scientific practices,” the university said.

He Jiankui has been under intense scrutiny since November, when he announced the birth of twin girls whose genomes he claimed to have edited using CRISPR–Cas9 technology. Shortly after, a Chinese government report said that He had “seriously violated ethics, scientific research integrity and relevant state regulations”.

The professors whose actions Stanford reviewed are bioengineer Stephen Quake, bioethicist William Hurlbut and geneticist Matthew Porteus, all of whom have been identified in previous media reports. In an interview with The New York Times on 16 April, Quake said he was relieved that the inquiry was over, and that its findings are “consistent with what I knew to be true”.