He's unverified claim came on the eve of an worldwide summit dedicated to discussing the emerging science and ethics around powerful tools that give scientists unprecedented potential to tweak traits and eliminate genetic diseases - but that have raised fears of "designer babies".
"Using these technologies prematurely can really adversely impact the entire scientific field", Caulfield went on.
The committee organizing the Hong Kong conference where He is due to speak - the Second International Summit on Human Genome Editing - said in a statement on Monday it had only just been informed of He's work on the genes of the twin girls.
He is a research professor at China's Southern University of Science and Technology in the southern city of Shenzhen. According to He, two of these embryos resulted in a pregnancy, and twin girls (Lulu and Nana, which are pseudonyms) were born. There was no independent confirmation of He's work and he did not provide written documentation of his research.
"If true, this experiment is monstrous", said Julian Savulescu, a medical ethics specialist at Britain's University of Oxford.
More than 120 Chinese scientists signed a letter condemning the claim by He. But when it comes to embryos, those changes can be inherited by future generations.
In this October 9, 2018 photo, Zhou Xiaoqin adjusts a monitor showing a video feed of a fine glass pipette containing Cas9 protein and PCSK9 sgRNA to an embryo under a microscope at a laboratory in Shenzhen in southern China's Guangdong province.
In interviews, He Jiankui defended his work.
Jiankui's research has not been independently verified or published though he feels confident in his findings: "I feel a strong responsibility that it's not just to make a first, but also make it an example", he told the AP. He told The Associated Press, adding that "society will decide what to do next".
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He had studied in the past at Rice and Stanford universities in the United States. "The biology department's academic commission holds that he has severely violated our academic ethics and principles", the university said.
The Shenzhen university distanced itself from He in a statement Monday that said the researcher had been on unpaid leave from February 1, 2018 and was not expected to return until January 2021.
The National Health Commission has ordered local officials in Guangdong province to investigate He's actions, and his employer, Southern University of Science and Technology, is investigating as well. The Harvard geneticist George Church has said that he thinks that the research is "justifiable".
In this October 9, 2018 photo, a microplate containing embryos that have been injected with Cas9 protein and PCSK9 sgRNA is seen in a laboratory in Shenzhen in southern China's Guangdong province.
On Thursday, the organising committee of the summit will present a report summarising on how to carry forward the development of gene editing.
The CRISPR tool is a recently developed tool for adding necessary genes or disabling harmful ones to treat diseases in adults, though the USA only allows it to be used in lab research.
The gene editing was allegedly done during IVF, a process in which a sperm fertilizes an egg in a laboratory, and the embryo is implanted in a womb. In the USA, the process is only permitted for lab research. "This suggests that the research of gene editing in China not only has a promising potential, but also is responding to the public's needs".
Joyce Harper, a professor in genetics and human embryology at the Institute for Women's Health at University College London, described the alleged research "premature, risky and irresponsible", calling for public debate and legislation. He sought to disable a gene called CCR5 that forms a protein doorway that allows HIV, the virus that causes AIDS, to enter a cell. It raised deep questions for scientists about whether traditional oversight channels were followed, as well as what to believe about the experiment and the results. But Snelling said that was too great a risk to the babies when there were other, safer ways to prevent HIV transmission to a fetus.