A group of scientists in China claim that they have helped bring two genetically edited twin babies to life. The goal in doing so was to bestow the twin girls with the ability to prevent HIV infection and avoid AIDS. The scientists claim they were successful, according to reports in Associated Press and MIT Tech Review.

The claims haven’t been independently verified, but if they are true, then both science and ethics have entered unchartered territories.

More than 100 Chinese scientists have co-signed a letter, released on China’s social media site Weibo, condemning the experiment for using gene-editing technology on humans. The signatories include scientists from some of China’s most prominent universities and from overseas institutes like MIT.

Quartz has translated the letter into English.

Regarding the recent news from domestic and foreign media on human embryo gene-editing and two babies born using CRISPR technology, as rational human beings, with respect for scientific theories and concerns regarding the future scientific developments in China, our statement is as follows:

The bioethics approval for this so-called “study” was insufficient. We can only use the word “crazy” to describe the experiment conducted directly on human beings. We have much to debate inside the scientific community about the accuracy and off-target-effects brought by CRISPR. Any attempts to alter human embryos and make babies carry huge risks without strict examination beforehand. It is scientifically possible, but scientists and medical experts have chosen not to use the technology on human beings because of uncertainties, risks, and most importantly, the ethical problems that follow. Such irreversible alterations on human genes will inevitably go into the human gene pool. We should have a thorough and in-depth discussion with scientists and people across the world about these potential effects. We cannot rule out the possibility that the babies, born using this technology, can be healthy for a period of time. But the potential risks and dangers brought along by the unjustified procedure, especially if such experiments carry on, are hard to measure. At the same time, this is a strike at the reputation and development of China’s science, especially in biomedical research. It’s extremely unfair to most of the scientists and scholars who work hard to innovate and adhere to ethical guidelines. We urge related regulatory departments and affiliated research institutes to establish laws and regulations on [gene-editing], and conduct a full investigation. They should also reveal the findings to the public. Pandora’s Box has been opened. We need to close it before we lose our last chance. We as biomedical researchers strongly oppose and condemn any attempts on editing human embryo genes without scrutiny on ethics and safety!

Signed by 122 scientists:

Bi Guoqiang, University of Science and Technology of China

Cai Xuyu, West China Hospital, Sichuan University

Cang Chunlei, University of Science and Technology of China

Cao Gang, Huazhong Agricultural University

Chen Xiaoke, Stanford University

Chen Yelin, Interdisciplinary Research Center on Biology and Chemistry

Chen Yongjun, Guangzhou University of Chinese Medicine

Chen Yu, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences

Chou Zilong, Institute of Neuroscience, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences

Deng Chunshan, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences

Dong Peng, Janelia Research Campus, Howard Hughes Medical Institute

Dong Wei, South West Medical University

Dong Zhifang, Chongqing Medical University

Fan Pu, Chinese Academy of Medical Sciences, Basic Medical Science Institute

Fei Jifeng, Institute for Brain Research and Rehabilitation, South China Normal University

Feng Weijun, Fudan University

Fu Yu, Agency for Science, Technology and Research

Ge Wuping, the University of Texas Southwestern Medical Center

Gong Hui, the Huazhong University of Science and Technology

Gu Yu, Fudan University

Guan Jisong, School of Life and Science, ShanghaiTech University

Guo Yiping, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences

Han Yungeng, School of Basic Medicine, Huazhong University of Science and Technology

He Kaiwen, Interdisciplinary Research Center on Biology and Chemistry

He Miao, Fudan University

He Shuijin, ShanghaiTech University

Hu Ronggui, Shanghai Institute for Biological Sciences, China Academy of Sciences

Huang Lianyan, Zhongshan School of Medicine, Sun Yat-Sen University

Huang Rui, Chongqing University

Jia Jiemin, Westlake University

Jiang Man, the Huazhong University of Science and Technology

Xie Yunli, Fudan University

Jin Xinchun, Suzhou University

Kang Lihui, Zhejiang University School of Medicine

Ke Jiangbin, Sun Yat-Sen University

Lei Peng, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University

Li Anan, Xuzhou Medical University

Li Boxing, Sun Yat-Sen University

Li Chengyu, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences

Li Huiliang, University College London

Li Lu, Sun Yat-Sen University

Li Nan, Massachusetts Institute of Technology

Li Qian, Shanghai Jiaotong University, School of Medicine

Li Yan, Institute of Biophysics, Chinese Academy of Sciences

Li Yanqing, Tsinghua University

Li Yulong, Peking University

Liang Feixue, Southern Medical University

Liang Zhifeng, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences

Lin Sen, Army Medical University

Liu Haikun, German Cancer Research Center

Liu Huisheng, Beihang University

Liu Kai, the Hong Kong University of Science and Technology

Liu Qiang, the University of Science and Technology of China

Lu Qi, School of Medicine, Wayne State

Luo Huan, Peking University

Lu Hui, the George Washington University

Ma Chaolin, Nanchang University

Ma Huan, Zhejiang University School of Medicine

Ma Quanhong, Suzhou University

Ma Yuanye, Kunming University of Science and Technology

Mao Yu, Kunming Institute of Zoology, China Academy of Sciences

Mei Lin, Case Western Reserve University

Pan Bingxing, Nanchang University

Pan Yufeng, Institute of Life Sciences, Southeast University

Pang Zhiping, Rutgers University

Peng Bo, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences

Peng Jiyun, Nanchang University

Qin Song, Fudan University

Qu Yibo, Jinan University

Ren Chaoran, Jinan University

Shao Zhiyong, Fudan University

Shen Qin, Tongji University

Sheng Nengyin, Kunming Institute of Zoology, China Academy of Sciences

Shi Lei, Jinan University

Song Yan, Peking University

Song Binggui, Zhejiang University, School of Medicine

Sun Wenzhi, Chinese Institute for Brain Research, Beijing

Sun Xiangdong, Guangzhou Medical University

Sun Xiaoli, Fudan University

Sun Yi, Tongji University

Qian Hongtao, Hunan University

Tan Guohe, Guangxi Medical University

Tao Yanmei, Institute of Life Sciences, Hangzhou Normal University

Tong Xiajing, ShanghaiTech University

Tu Jie, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences

Wang Hao, Zhejiang University

Wang Shirong, Beijing Institute of Technology

Wang Fei, China Medical University

Wang Liming, Zhejiang University, School of Medicine

Wang Liping, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences

Wang Liang, Zhejiang University, School of Medicine

Wang Lupeng, National Institutes of Health

Wang Shouyan, Fudan University

Wang Wenyuan, Shanghai Institute of Organic Chemistry, China Academy of Sciences

Wang Xiaoqin, Tsinghua University

Wang Xiaodong, Zhejiang University, School of Medicine

Wang Xiaoqun, Institute of Biophysics, Chinese Academy of Sciences

Wu Qingfeng, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences

Wu Longjun, Mayo Clinic College of Medicine and Science

Xiao Xiao, Fudan University

Xiong Wei, Tsinghua University

Xiong Wei, University of Science and Technology of China

Xu Nanjie, Shanghai Jiaotong University, School of Medicine

Xu Ying, Suzhou University

Xu Zhenzhong, Zhejiang University, School of Medicine

Xu Junyu, Zhejiang University

Xu Xiaohong, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences

Xu Zhiheng, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences

Xue Tian, the University of Science and Technology of China

Yang Yan, Institute of Biophysics, Chinese Academy of Sciences

Yang Yang, ShanghaiTech University

Yang Zhengang, Fudan University

Ye Haihong, Capital Medical University

Yu Yongchun, Fudan University

Yuan Kexin, Tsinghua University

Zhan Cheng, National Institutes of Biological Sciences, Beijing

Zhang Bo, Peking University Shenzhen Graduate School

Zhang Erquan, National Institutes of Biological Sciences, Beijing

Zhang Jiayi, Fudan University

Zhang Jie, Xiamen University

Zhang Luoying, Huazhong University of Science and Technology

Zhang Siyu, Shanghai Jiaotong University, School of Medicine