A Chinese court on Monday sentenced the scientist who claimed to be behind the world's first gene-edited babies to three years in prison for illegal medical practice, state media reported.
He Jiankui, who shocked the scientific community last year by announcing the birth of twin girls whose genes had allegedly been altered to confer immunity to HIV, was also fined three million yuan ($430,000), Xinhua news agency said.
He, who was educated at Stanford University, was sentenced by a court in Shenzhen for "illegally carrying out the human embryo gene-editing intended for reproduction", Xinhua said.
Two of his fellow researchers were also sentenced. Zhang Renli was handed a two-year jail term and fined one million yuan while Qin Jinzhou was given 18 months, suspended for two years, and fined 500,000 yuan.
The trio had not obtained qualifications to work as doctors and had knowingly violated China's regulations and ethical principles, according to the court verdict, Xinhua said.
They had acted "in the pursuit of personal fame and gain" and seriously "disrupted medical order", it said.
The researchers had forged ethical review materials and recruited couples where the husband was HIV positive for their gene-editing experiments.
The trial was held behind closed doors as the case related to "personal privacy", Xinhua said.
He's gene-editing experiments resulted in two pregnancies -- the twin girls and third baby which had not previously been confirmed, it said.
He announced in November last year that the world's first gene-edited babies -- the twins -- had been born that month after he altered their DNA to prevent them from contracting HIV by deleting a certain gene under a technique known as CRISPR.
Days later, He, a former associate professor at the Southern University of Science and Technology in Shenzhen, told a biomedical conference in Hong Kong he was "proud" of his gene-editing work.
The claim shocked scientists worldwide, raising questions about bioethics and putting a spotlight on China's lax oversight of scientific research.
"That technology is not safe," said Kiran Musunuru, a genetics professor at the University of Pennsylvania, explaining that the CRISPR molecular "scissors" often cut next to the targeted gene, causing unexpected mutations.
"It's very easy to do if you don't care about the consequences," Musunuru said.
Amid the outcry, He was placed under police investigation, the government ordered a halt to his research work and he was fired by his Chinese university.
Gene-editing for reproductive purposes is illegal in most countries. China's health ministry issued regulations in 2003 prohibiting gene-editing of human embryos, though the procedure is allowed for "non-reproductive purposes".
He's gene editing meant to immunise the twins against HIV may have failed in its purpose and created unintended mutations, scientists said earlier this month after the original research was published for the first time.
He claimed a medical breakthrough that could "control the HIV epidemic", but it was not clear whether he had even been successful in immunising the babies against the virus because the team did not reproduce the gene mutation that confers this resistance, scientists told the MIT Technology Review.
While the team targeted the right gene, they did not replicate the "Delta 32" variation required, instead creating novel edits whose effects are not clear.
Moreover, CRISPR remains an imperfect tool because it can lead to unwanted or "off-target" edits, making its use in humans hugely controversial.
In 2015, a UN bioethics committee called for a stop to human embryo gene editing for fears it could be used to modify the human race.
But a year later Britain granted scientists permission to edit embryo DNA in research on the causes of infertility and miscarriages.
And in 2017, a US science advisory committee said such modification should be allowed in future to eliminate disease.
In November this year the World Health Organization said it would create a global registry to track research into human genetic manipulation following the backlash to He's announcement.