Italian surgeon Sergio Canavero sparked controversy last year when he claimed to have conducted the world's first head transplant on a corpse in a Chinese hospital, the state-run Global Times reported at the time, though other scientists have called his claims overblown.
On Sunday He, who was educated at Stanford University, announced in a YouTube video he had used CRISPR, a technique that allows scientists to remove and replace a pin 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 applied it to treat cancer patients.
Qiu Renzong, former vice president of the Ethics Committee's Chinese health ministry, accused He of receiving a "fraudulent" ethics review by going to another hospital for review as opposed to getting approval from his own university, adding he was destroying the reputation of China's scientists .
Qiu said a 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 punish for misconduct.
"People say that the ministry is without teeth, can not bite people, so we try to bring the teeth to the head of the ministry, so they can bite people when people violate the regulations," he told reporters in English at a Gene-editing conference 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 adds.
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 laboratory in the southern Chinese city of Shenzhen, faces scrutiny on the mainland too, with the National Health Commission ordering a 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 was a "serious violation of academic ethics and norms".
A notice from Shenzhen's medical ethics authority said that all medical organizations must establish an ethics review committee before undertaking biomedical research on humans, and the ethics board of the hospital did not complete its registration as required.
He defended his research in another video, saying that he is trying to help families who carry genetic diseases.
"We believe that ethics is on our side of history, looking back to the 1970's with Louise Brown, and then the same fear and criticisms are now being repeated," he said, referring to the first person born in vitro fertilization.