A Chinese research team has touched off a wave of controversy after, for the first time, genetically modifying human embryos. The embryos were inviable, incapable of becoming living humans under any circumstances, and the team was less than completely successful. However, according to many an ethical line has been crossed and the researchers do not intend to stop after their work.

Rumors about the research have been buzzing around the internet for months, after having first been reported by MIT Technology Review. The rumours were confirmed this week by a paper in the journal Protein & Cell. The work was originally submitted to the journals Science and Nature but both rejected it due to the controversy.

Proponents of human embryonic genetic editing think that it can be used to eradicated genetic diseases and even genetic predispositions to certain diseases and disorders. It is even possible that genetic editing or modification could one day lead to enhanced capabilities in humans including strength and intelligence.

Opponents argue that the person the embryo grown into has no way of providing consent and that it could have unforeseen consequences that aren’t known until much later.

An op-ed in published in Nature last month, signed by several scientists urged their colleagues to stop modifying human embryos and the human genome generally. It called for an international discussion in an effort to reach consensus on the scientific and ethical questions involved. As advocates for greenhouse gas emission reductions have found, however, reaching international consensus on science issues is no easy task.

The Chinese researchers used an Crispr, a genome editing procedure, in an attempt to alter a gene that causes the life-threatening blood disorder beta-thalassaemia.

Led by Junjiu Huang at Sun Yat-sen University in Guangzhou they attempted the procedure in 86 faulty embryos and then waited 48 hours for the embryos to grow to about eight cells each. Of the 71 embryos that reached that size only 28 had been successfully spliced and even fewer contained the new genetic material.

The team also reported a number of off topic mutations which were probably caused by the Crispr editing.

“If you want to do it in normal embryos, you need to be close to 100%. That’s why we stopped. We still think it’s too immature,” Huang told Nature.

Dusko Ilic, a stem cell researcher at King’s College, London told the Guardian that the tests show how far this technology is from being ready for any kind of regular use.

“What the paper really emphasises is that we are far away from using genomic editing because it’s not safe. The idea of using this for designer babies is very far-fetched. The technology is too far off,” said Ilic.

Ilic added that he did not see the Chinese work in particular as unethical, because the abnormal embryos would have been discarded by any clinic in the world. He also does not think that this type of research is likely to stop.

“You cannot stop science. No matter what moratorium is proposed, you cannot stop this work continuing around the world,” he said.

According to Nature, there are at least four teams in China alone currently testing gene editing in human embryos