A Chinese university says it will immediately launch an investigation after an associate professor released videos on YouTube claiming to have edited the genes of twins born this month and defending the ethics of his work.

Key points: He Jiankui says he was able to copy and paste over defective genes

He Jiankui says he was able to copy and paste over defective genes Scientists says it's "massive blow" to reputation of Chinese science

Scientists says it's "massive blow" to reputation of Chinese science Many disputed veracity of Mr He's claims

The Southern University of Science and Technology in the southern Chinese city of Shenzhen said it had been unaware of the research project and that the academic, He Jiankui, had been on leave without pay since February.

The work is a "serious violation of academic ethics and standards", it said.

The university issued a statement after Dr He said in five videos posted on the video-sharing website on Monday 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 says in one video.

It was impossible to verify the claims as Dr He did not provide any written documentation of his research.

A 'monstrous' experiment

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 Dr He was 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.

Dr He defended his work and said he had been on voluntary leave for several years to focus on his research.

"I understand my work will be controversial, but I believe families need this technology. And I'm willing to take the criticism for them," he said.

In an earlier email, Dr He said he planned to share data about the trial at a scientific forum this week.

He said he planned for it to also 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.

"These healthy babies are being used as genetic guinea pigs. This is genetic Russian roulette," Mr Savulescu said.

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

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.

According to information listed on China's Clinical Trial Registry website, the study was sponsored by the Southern University of Science and Technology and Shenzhen HarMoniCare Women and Children's Hospital.

The listing also said the project was funded under a program run by the Shenzhen Government.

In April 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.

An embryo receives a small dose of Cas9 protein and PCSK9 sgRNA in a sperm injection microscope in a laboratory in Shenzhen. ( AP: Mark Schiefelbein )

Chinese scientists furious at experiment

China's National Health Commission issued a brief statement on its website saying it was "highly concerned" and "immediately ordered" the provincial health authority — the Health Commission of Guangdong Province — "to seriously investigate and clarify the matter".

He Jiankui is facing widespread condemnation. ( AP: Mark Schiefelbein )

"We are upholding the principles of [being] highly responsible for the people's health and being scientific, we will act on this according to the law and inform the public in time," it said in the statement.

Dr He's experiment raised ire among his peers at home in addition to those abroad.

In an open-letter published on the Weibo account Zhishifenzi (The Intellectuals), a group of 122 biomedical scientists spoke of the threat it posed to humans and the implications for the reputations of Chinese scientists.

"The so-called biomedical ethical review of this study was actually existing in name only," the letter read.

"Direct human experiments [without ethical assessment] can only be described as madness.

"The accuracy of CRISPR gene-editing technology and its miss-target effect are very controversial in the scientist community.

"Any attempt to directly transform human embryos and produce babies has massive risks.

"At the same time, this is a massive blow to the global reputation and development of China's science, especially in the field of biomedical research."

ABC/Reuters