The Italian surgeon Sergio Canavero sparked controversy last year when he claimed to have conducted the world's first head transplant on a corpse at a Chinese hospital, the state-run Global Times reported at the time, although other scientists have called their claims overblown.
On Sunday He, who was educated at Stanford University, announced in a YouTube video that he had used CRISPR, a technique that allows scientists to remove and replace a strand with pinpoint precision, to modify the twins' DNA.
The tool has not been used in human trials in the United States, although doctors in China have been applying it to treat cancer patients.
Qiu Renzong, former vice president of the Chinese health minister's ethics committee, accused him of obtaining a "fraudulent" ethics review by going to another hospital for review as opposed to obtaining approval from his own university, adding he was destroying the reputation of Chinese scientists .
Qiu said that lack of regulation means that scientists often face no punishments as they are only required to abide by the rules of their institutions, which may not stipulate punishments for misconduct.
"People say the minister is without teeth, can not bite people. So we try to provide the teeth to the minister head, so they can muzzle people when people violate the regulations," he told reporters in English at a conference editing gene in Hong Kong.
"The mainland is very protective of scientists, if you make some small mistake, that's the end of it, there's no punishment. I suggest that they should be punished," he added.
With a skeptical research community waiting for evidence of His claims, the scientist is expected to speak at the same conference in Hong Kong on Wednesday and Thursday.
He, who works from a lab in the southern Chinese city of Shenzhen, faces scrutiny on the mainland too, with the National Health Commission ordering an investigation into the case.
A group of 122 Chinese scientists signed a joint statement calling the experiment "crazy" and said it was unfair to other scientists who stick to "the moral bottom line."
The Southern University of Science and Technology, where He Works, said he had been on unpaid leave since February and his research is a "serious violation of academic ethics and norms."
A notice from Shenzhen's medical ethics authority said that all medical organizations should establish an ethics review committee before undertaking biomedical research on humans, and the ethics board of the hospital involved had not completed its registration as required.
He has defended his research in another video, saying that he is trying to help families who carry genetic diseases.
"We believe ethics are on our side of history. Look back to the 1970s with Louise Brown. The same fears and criticisms are now repeated," he said, referring to the first person to be born through in vitro fertilization.