A Chinese scientist who shocked the medical community last year when he said he had illegally created the world's first gene-edited babies has been sentenced to three years in prison by a court in southern China.

He Jiankui announced in November 2018 that he used a powerful technique called CRISPR on a human embryo to edit the genes of twin girls. He said he modified a gene with the intention of protecting the girls against HIV, the virus that causes AIDS. Many scientists expressed concerns about possible unintended side effects of the genetic changes that could be passed down to future generations.

Last fall, He also indicated that there might be another pregnancy involving a gene-edited embryo. The court indicated that three genetically edited babies have been born.

The closed court in Shenzhen found He and two colleagues guilty of illegal medical practice by knowingly violating the country's regulations and ethical principles with their experiments, Xinhua news agency reported. It also ordered He to pay a fine of about $430,000.

He's colleagues, Zhang Renli and Qin Jinzhou, were handed lesser sentences and fines.

"None of the three defendants acquired doctor's qualifications. [They] craved fame and fortune, and deliberately went against the country's regulations on scientific research and medical management. [They] went beyond the bottom lines of scientific research and medical ethics," the court stated, according to the South China Morning Post.

He has defended his controversial work by saying that it will help families. "I understand my work will be controversial," he said, as NPR's Rob Stein reported. "But I believe families need this technology. And I am willing to take the criticism for them."

At the time, scientists had previously genetically modified human embryos, but none had publicly claimed to have implanted embryos in a woman's womb in an experiment that resulted in human babies.

Chinese police detained He in January and, as the Post reported, an initial investigation concluded that he "organised a project team that included foreign staff, which intentionally avoided surveillance and used technology of uncertain safety and effectiveness to perform human embryo gene-editing activity with the purpose of reproduction, which is officially banned in the country."

The gene that He edited, CCR5, is known as a pathway for HIV to infect immune system cells. But as Stein notes, research carried out since He's stunning announcement has suggested that the genetic changes he made could cause more harm than good to the babies' health.

A study in Nature Medicine analyzed the DNA of more than 400,000 people and found that the changes that He made could make people more vulnerable to viruses such as West Nile and influenza.

"This is a lesson in humility," George Daley, the dean of the Harvard Medical School, told Stein. "Even when we think we know something about a gene, we can always be surprised and even startled, like in this case, to find out that a gene we thought was protective may actually be a problem."

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