A team led by Prof He Jiankui says the twin girls, born a few weeks ago, had their DNA altered as embryos to prevent them from contracting HIV.  The team at  the Southern University of Science and Technology, in Shenzhen, has been recruiting couples to create the first gene-edited babies. The aim is to eliminate a gene called CCR5 using gene-editing tool CRISPR, in the hope of making the offspring resistant to HIV, smallpox and cholera.

Experiments like this, modifying the genome of human babies, are banned  in most of the developed world.  he scientist behind the effort, He Jiankui, has declined to comment.  The technology already exist for other mammals so achieving this in humans  would be less a stunning medical achievement but a controversial step that may lead down  a slippery slope to a new form of eugenics. The technology is ethically charged because changes to an embryo would be inherited by future generations and could eventually affect the entire gene pool.

It is  not clear if He Jiankui, obtained special permission or ignored the law in China that bans this soprt of experiment in humans.
Shifting views: A recent opinion poll carried out by Sun Yat-Sen University found 60% of the 4,700 Chinese surveyed would support legalizing edited children if the goal was to treat or prevent disease. Polls have found similar levels of support in the US for gene editing. But there is very little support for “designer babies” whose physical looks or personality has been changed.