What did He Jiankui do, and why did the world object?

In November 2018, the Chinese scientist He Jiankui announced that he had created the first genetically edited human babies: twin girls, known as Lulu and Nana, born in October 2018 and said to be edited for HIV resistance. He first announced it on YouTube, then presented it at the Second International Summit on Human Genome Editing in Hong Kong. He said he had used CRISPR/Cas9 to edit a gene called CCR5, which codes for a protein HIV-1 uses to enter cells, to create a mutation that few people naturally have and that possibly confers resistance to HIV-1.

The announcement was first praised in the press as a major advance, but scrutiny turned it into widespread condemnation. It was not disclosed whether the experiment had had proper ethical review, it was unclear whether participants gave truly informed consent, and by his own account the girls still carried functional copies of CCR5 and were not protected from forms of HIV that use a different receptor. The NIH called the medical necessity utterly unconvincing and the informed consent highly questionable.

His research was suspended on 29 November 2018 and he was fired on 21 January 2019. On 30 December 2019 a Chinese court found him guilty of illegal practice of medicine and sentenced him to three years in prison, and he was released in April 2022.

Not all reactions were identical. George Church called gene editing for HIV resistance justifiable, though he questioned the decision to use one of the embryos for a pregnancy attempt, and Arthur Caplan said such engineering is inevitable. Laws are not counted the same way everywhere, but one 2020 tally of national policies found no country that permits germline engineering for reproduction.