Chinese health and medical ethics authorities started an investigation on Monday into claims by a scientist who released videos on YouTube, saying he had altered the genes of twins born earlier this month, creating the first gene edited babies.

Earlier, the Southern University of Science and Technology in Shenzhen, where the scientist, He Jiankui, holds an associate professorship, said it had been unaware of the research project and that Mr. He had been on leave without pay since February.

The work is a serious violation of academic ethics and standards , the University said.

The university issued a statement after Mr. He said in five videos posted on Monday that he used a gene-editing technology known as CRISPR-Cas9 to edit the genes of twin girls.

The editing process, which he calls gene surgery,  worked safely as intended  and the girls are  as healthy as any other babies , he said in one video. It was impossible to verify the claims as Mr. He did not provide any written documentation of his research.

Cutting-and-pasting DNA

CRISPR-Cas9 is a technology that allows scientists to essentially cut-and-paste DNA, raising hope of genetic fixes for disease. However, there are also concerns about its safety and ethics.

 If true, this experiment is monstrous,  said Julian Savulescu, director of the Oxford Uehiro Centre for Practical Ethics at the University of Oxford.

Southern University of Science and Technology said it would form an independent committee of experts to investigate. It said Mr. He is on unpaid leave until 2021.

 Southern University of Science and Technology strictly requires scientific research to conform to national laws and regulations and to respect and comply with international academic ethics and standards, it said.

In the videos, the scientist defended his work:  I understand my work will be controversial, but I believe families need this technology. And I am willing to take the criticism for them.

In an earlier email to Reuters, Mr. He said that he planned to share data about the trial at a scientific forum this week. Mr. He will also let his work to go “through the peer review process, and through a pre-print soon.  A pre-print is a publication of findings made before the research is published in a peer-reviewed journal.

The MIT Technology Review and the Associated Press first reported on Mr. He’s latest work.

 Protection against HIV

Earlier, Mr. He said he was aiming to bestow on the gene edited babies  lifetime protection  against HIV, the virus that causes AIDS.

Mr. He said he began his work in the second half of 2017 and enrolled eight couples. All of the potential fathers involved were HIV-positive. Five chose to implant embryos, including the parents of the twin girls, identified only by the pseudonyms Mark and Grace. The babies  names are Lulu and Nana, He said in one video.

In 2015, scientists at Sun Yat-sen University sparked a global controversy after they published results of an experiment that used CRISPR-Cas9 to edit the genes of non-viable human embryos.

Describing Mr. He s work, Mr. Savulescu said:  These healthy babies are being used as genetic guinea pigs. This is genetic Russian Roulette.