Update 11/28/18: This article has been updated to reflect additional information from campus professor and co-discoverer of CRISRP-Cas9 Jennifer Doudna. 

Chinese scientist He Jiankui announced Monday that he created the world’s first genetically edited babies with the gene-editing technology CRISPR-Cas9, prompting pushback from members of the scientific community over ethical concerns.

He claimed that he recruited seven couples in which the father had HIV. The scientist said he then altered their embryos’ DNA to prevent the children from contracting HIV. Out of the seven couples, one pregnancy occurred thus far from which genetically modified twins — Nana and Lulu — were born. This experiment had yet to be confirmed by outside scientists as of press time.

Campus professor Jennifer Doudna co-discovered the CRISPR-Cas9 technology, which allows scientists to make quick and precise edits to genetic material. In the past, Doudna has expressed concerns about potential unethical applications of CRISPR, and she released a statement Monday morning regarding reports of He’s experiment.

“It is imperative that the scientists responsible for this work fully explain their break from the global consensus that application of CRISPR-Cas9 for human germline editing should not proceed at the present time,” Doudna said in a statement published Monday on Berkeley News.

The news of He’s experiment came just before the start of the Second International Summit on Human Genome Editing, taking place from Nov. 27 to Nov. 29 in Hong Kong. Researchers and scientists around the world, including Doudna, will discuss at the conference questions about gene editing as well as its applications, ethics and the governance of human genome editing, according to the summit website.

While He’s work was revealed just this week, Mark DeWitt, a project scientist at the Innovative Genomics Institute, or IGI, said He entrusted him with intent to conduct the experiment about a year ago. IGI is a partnership between UC Berkeley and UCSF to improve human health through the use of CRISPR.

DeWitt said he met He at a talk in China and that DeWitt learned after they stayed in contact about He’s intent to use CRISPR technology on human embryos. DeWitt added that media reports about He’s experiment differed significantly from DeWitt’s initial understanding of the research and that the recent reports raise “serious concerns” about the ethics of the methodology.

“As for the ethics of gene editing to prevent disease … it’s not even relevant,” DeWitt said. “It’s how he went about it. There’s a reason why we have regulations.”

DeWitt is among the scientists concerned by the conditions under which He conducted his experiment and whether it was done with the proper regulatory approval. DeWitt said that if the allegations about He’s work are true, the experiment may have been medically unethical.

Doudna echoed DeWitt’s sentiment in an emailed statement, calling He’s work “reckless” and “damaging” to the social acceptance of CRISPR’s development. Aside from the scientific impact of He’s experiment, Doudna said in the statement that she is concerned about the well-being of the twins.

IGI policy analyst Lea Witkowsky said she was shocked and disappointed when she heard the reports about He’s work because of the experiment’s alleged secrecy and lack of peer review.

“There was no outside oversight or even proper local oversight, as far as we can tell,” Witkowsky said. “This is directly in contrast to the scientific method of peer review. This did not undergo any of these standards.”

According to Witkowsky, there are no internationally binding regulations on the use of CRISPR technology, but DeWitt said He could face consequences in China for these allegations. Doudna said in the statement, however, that human embryo editing is prohibited in the United States and is also banned in multiple European countries.

Witkowsky hopes the reported CRISPR application to human genomes could prompt a larger conversation about germline editing within the scientific community, governments and the general public.

“The global scientific community has reacted strongly against this work,” Doudna said in the statement. “There will be calls for verification of his claims, as well as re-doubled efforts to put in place both specific criteria for clinical use of CRISPR-Cas9 and consequences for ignoring those criteria.”