Japanese researchers have succeeded in converting embryonic induced pluripotent stem cells from laboratory mice into healthy sperm, and ultimately produced healthy and reproductively capable mice, which is expected to be a boon for male infertility. Japan’s Kyoto University Professor Tomonori Saito and others said in the United States “Cell” online version of the journal, they will be experimental mouse embryonic stem cells into primitive germ cells, implanted in the body of experimental mice can not produce sperm normally, the primitive germ cells began to produce a normal form of sperm, and can make the fertilization of the egg. The offspring of the implanted fertilized eggs were healthy, developed normally, and were capable of reproduction in both males and females. Professor Tomonori Saito, who led the study, believes that the same process can be accomplished using induced pluripotent stem cells taken from the skin. Dr. Jane Stewart, a British gynecologist, said that the technique of growing gametes (egg cells or sperm) or gamete germ cells in the laboratory is “a milestone in the field of research into fertility issues and related treatments”. Alan Percy, a professor of men’s science at the University of Sheffield in the United Kingdom, said the research “is of great significance to our understanding of how sperm are produced, and perhaps one day we will be able to use this technique to develop human sperm”. At the same time, he also said that many researchers have tried to use stem cells to recreate the sperm production process in the laboratory, but so far no study has achieved perfect success. Research into the use of stem cells to produce “artificial sperm” has a long history. As early as 2003, several research groups claimed to have created “artificial sperm,” but efforts to impregnate lab rats ended in failure. 2006, a research group at Newcastle University in the United Kingdom used embryonic stem cells to create “artificial sperm” and bred seven mice. In 2006, a team of researchers at the University of Newcastle upon Tyne used embryonic stem cells to create “artificial sperm” and bred seven mice, but all seven mice developed health problems and died prematurely. Some scientists were thrilled with the news of the successful development of “artificial sperm” and called it a huge breakthrough. But some scientists say there are still many technical and ethical challenges to overcome before the technology can be applied to humans.