Fears grow over claim of gene-edited babies

The work is highly controversial because the changes can be inherited and could go on to harm other genes, and is banned in many countries.
The scientist, Mr He, said twin girls born earlier this month had DNA altered to make them resistant to possible future infection with HIV.
Mr He said: "They need this protection since a vaccine is not available."
Jennifer Doudna, a University of California-Berkeley scientist and one of the inventors of the CRISPR gene editing tool which Mr He claimed to have used, said: "This is a truly unacceptable development.
"I'm grateful that he appeared today, but I don't think that we heard answers. We still need to understand the motivation for this."
David Liu of Harvard and MIT's Broad Institute, the inventor of a variation of the gene editing tool, said: "I feel more disturbed now.
Leading scientists have raised more questions after a Chinese scientist repeated his claim that he helped make the world's first gene-edited babies.
He Jiankui spoke at a meeting on gene editing in Hong Kong where the conference leader called his experiment "irresponsible", and said it provided evidence that the scientific community had failed to regulate itself to prevent premature efforts to alter human DNA.
There is no independent confirmation of Mr He's claim and he has not yet published in any scientific journal where his work would be vetted by experts.
At the conference, Mr He failed or refused to answer many questions, including: who funded him, how did he ensure that participants understood the potential risks and benefits, and why did he keep his work secret until after it was done?
After Mr He spoke, David Baltimore, a Nobel laureate from the California Institute of Technology and a leader of the conference, said the scientist's work "would still be considered irresponsible" because it did not meet criteria many scientists agreed on several years ago before gene editing could be considered.
Mr Baltimore said: "I personally don't think that it was medically necessary."
The case shows "there has been a failure of self-regulation by the scientific community" and said the conference committee would meet and issue a statement on Thursday about the future of the field, Mr Baltimore added.
Regulators have been swift to condemn the experiment as unethical and unscientific.
China's National Health Commission has ordered local officials in Guangdong province to investigate Mr He's actions, and his employer, Southern University of Science and Technology of China, is also investigating.