"Lulu and Nana were born normal and healthy", he told a rapt audience at a Human Genome Editing Conference in Hong Kong, referring to the twins by pseudonyms.
Gene-editing is banned in the U.S. because the DNA changes could be passed onto future humans and it risks harming other genes as well as people's immune systems, the Associated Press reported on Monday.
The genes were edited to prevent the embryos from being able to contract, He said, noting that the twins' father had the virus.
The leaders of the Second International Summit on Human Genome Editing issued a statement Thursday on the last day of their conference in Hong Kong criticizing He Jiankui's claim as "deeply disturbing". According to Mazhar Adli, a researcher at the University of Virginia School of Medicine: "Deleting a single gene may not only alter how other genes are going to function but also may alter the overall behavior of the cell and the phenotype of [the] organism". When asked whether their genotype might affect their upbringing, he said, "I don't have to answer this question".
Speaking in a question-and-answer session after He's presentation on Wednesday, Baltimore said the case showed that "there has been a failure of self-regulation by the scientific community because of the lack of transparency". CRISPR has been hailed as an innovation with tremendous potential, but many in the scientific community believe the technology is still experimental and not ready for human application. It has also violated the ethical bottom line that the academic community adheres to.More news: Lawmakers criticise Facebook's Zuckerberg for United Kingdom parliament no-show
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The country's vice minister of science and technology, Xu Nanping, told state media outlet CCTV that the government was opposed to what He had done and said an investigation would soon be underway.
"I think we still need to understand the motivation for the study and what the process was for informed consent", said Jennifer Doudna, a co-inventor of the CRISPR gene-editing tool, who watched He speak.
China's National Health Commission has ordered an investigation into He Jiankui's experiment, which was condemned by the scientific community in China and overseas.
Chinese scientists have also condemned the work and the Southern University of Science and Technology, where He is on leave from his position as an associate professor, has announced an investigation.
He, who said he was against gene enhancement, said eight couples were initially enrolled for his study while one dropped out.
He, who was educated at Stanford University, said the twins' DNA was modified using CRISPR, a technique which allows scientists to remove and replace a strand with pinpoint precision. "Only found out about it after it happened and the children were born", Baltimore said.