He may (or may not) have brought about the world's first genetically modified human babies using CRISPR-Cas9, but He Jiankui's shoes are probably not the most comfortable in the world right now.

According to reports from Chinese media, the geneticist's whereabouts are currently unknown.

It's been reported that he is under house arrest at the Southern University of Science and Technology in Shenzhen, China, the institution that employs him, and from which he has been on leave since February.

However, the university has denied this, a spokeswoman telling the South China Morning Post, "Right now nobody's information is accurate, only the official channels are."

He has not been seen in public since Wednesday last week, when he attended the Second International Summit on Human Genome Editing in Hong Kong to clarify his claims.

He rattled the world last week when, in an interview with the Associated Press, and then a series of YouTube videos, he announced that he had successfully edited the genome of human embryos using CRISPR-Cas9 - and then those embryos, twin girls, had been successfully brought to term.

This - if He's claims are true, and there are those who believe they are, even though they are yet to be independently verified - would be huge.

Not just because they would be the first "designer babies" in the world, but because He seemingly conducted this experiment without any oversight or approval, and against regulations.

It's a massive ethical misstep, and the scientific community has widely criticised his actions.

Among the reasons for this: first, we don't know the long-term risks. Second, He edited something completely unnecessary. Third, it was a germline edit - meaning it will be passed down to those babies' offspring. Fourth, he did all this without any transparency. Fifth, this will absolutely shake the public's trust in the future use of CRISPR-Cas9.

According to Chinese news agency Xinhua, Chinese authorities have denounced the experiment as "extremely abominable in nature" and a violation of Chinese laws, via vice minister of science and technology Xu Nanping.

The Southern University of Science and Technology released a statement distancing itself from He's work, saying it "seriously violates academic ethics and academic norms."

The Chinese science union has also condemned the research, announcing that it "resolutely opposes so-called scientific researches and biotech applications that violate the spirit of science and ethics."

He is facing investigation from the Southern University of Science and Technology, as well as China's Ministry of Science and Technology, which has banned him from conducting any further research, the South China Morning Post reports.

His colleague, bioengineering professor Michael Deem of Rice University in the US, is also under investigation for his potential role in the proceedings.

If officials at the university have any knowledge of the geneticist's whereabouts, they are keeping it to themselves.

"We cannot answer any questions regarding the matter right now, but if we have any information, we will update it through our official channels," the spokeswoman said.