“The Chinese system is not transparent in any way,” said Arthur L. Caplan, a medical ethicist at New York University. “I do not trust Chinese bioethical deliberation or policy. Add healthy doses of politics, national pride and entrepreneurship, and it is tough to know what is going on.”

Image Photographs on the walls of Dr. Ren’s lab at Harbin Medical University showed his experiments on body transplants in mice. The mice lived only for a day after the procedure. Credit... Gilles Sabrie for The New York Times

Some Chinese researchers are also concerned that the experimentation is going too far, too fast.

“I don’t want to see China’s scholars, transplant doctors and scientists deepening the impression that people have of us internationally, that when Chinese people do things they have no bottom line — that anything goes,” said Cong Yali, a medical ethicist at Peking University, referring to Dr. Ren’s plans.

The Chinese government invested 1.42 trillion renminbi ($216 billion) in scientific research and development last year, compared with 245 billion renminbi in 2005, according to the National Bureau of Statistics.

Last year, researchers at Sun Yat-sen University, in the southern city of Guangzhou, altered a gene in the human embryo that causes thalassemia, a rare blood disease, using a technique developed in the United States. The experiment crossed an ethical line, some scientists in China and abroad said, because the changes would be inheritable if conducted on viable embryos. (The experiment used unviable embryos.) That could pave the way for permanent gene modification for qualities such as looks or intelligence.

Despite the concerns, in April another team in Guangzhou altered embryos to make them H.I.V. resistant. Internationally, some scientists criticized the experiment, citing a lack of consensus on the ethics of such work.

The team, from Guangzhou Medical University, said that “significant technical issues remain to be addressed.” It added that on ethical grounds it would not advocate genome editing on viable lines “until after a rigorous and thorough evaluation and discussion are undertaken by the global research and ethics communities.”