Japanese scientists have successfully grown test-tube sperm in the lab, a small but very significant first step toward using test-tube sperm to treat male infertility. In the lab, researchers extracted stem cells from rats and grew sperm. This breakthrough could help develop new treatments and drugs for currently infertile men. In vitro sperm technology has given hope to teenagers undergoing chemotherapy or radiation therapy for testicular cancer. With the help of this technology, they are able to have the right to be a father when they grow up to adulthood. Sperm grown in test tubes comes from stem cells extracted from the testes of newborn rats. The researchers implanted the stem cells into eggs and successfully produced 12 healthy mouse babies, four males and eight females. All of the mice are fertile and can reproduce the next generation after they have matured. Dr. Takehiko Ogawa, a urologist at Yokohama University in Japan, said that growing sperm in a test tube is one of the most complicated processes. Never before have scientists grown any mammalian sperm in a test tube. The Japanese researchers achieved this breakthrough by placing most of the cellular components of the testes into a petri dish while monitoring the entire process of stem cell development into sperm cells. Following this, they used in vitro fertilization to produce fertile mice. They said, “We used these sperm to produce healthy and fertile offspring.” The findings were published in the journal Nature. The testicular tissue remained functionally normal after being frozen in liquid nitrogen and was still usable after a few weeks, suggesting that it would be feasible to apply the technique to humans in a few years’ time, allowing infertile men to have children that are truly their own. Takehiko Ogawa and colleagues noted, “Our study shows that it is possible to grow healthy and intact mouse sperm in a test tube, an organ culture environment without a circulatory system. With continuous improvement and a personalized culture environment, this technique can be applied to a range of other species.” Commenting on the study in the journal Nature, Professor Shahian Rafi and oncologist Mark Schoendel noted that the technique offers hope for adolescent cancer patients. Adult cancer patients freeze their sperm before undergoing treatment, but this method is apparently not applicable to teenage cancer patients. Cultivating mature sperm in a lab dish is a remarkable breakthrough, and reproductive biologists and researchers have been trying this in rats for decades. Preserving sperm for patients who require treatments such as chemotherapy or radiotherapy is a very important practice, as sperm will inevitably be damaged during the course of these treatments,” said Raffi and Shaundel. For adult men, this problem can be solved by depositing sperm in a sperm bank prior to treatment. The technology developed in Japan can be a boon to adolescent patients who are in the midst of puberty. In other words, adolescent patients can receive a testicular biopsy and have it frozen before undergoing chemotherapy or radiation therapy to preserve their fertility. In the event of infertility, the testicular sections can be thawed and used to grow sperm in test tubes.” Dr. Alan Pacey, a fertility specialist at the University of Sheffield, noted that “this is a small but very important step.” He said, “This is a very interesting study. Scientists have been growing animal sperm in laboratories in various ways for a long time. Until now, no one has really succeeded, and the sperm produced have failed to produce healthy offspring, dying soon after birth. This technology could help develop new drugs and therapies to help infertile men produce more or healthier sperm, in addition to helping some men preserve their fertility. In my opinion, this is a small but very important step in understanding how sperm are formed and could make it possible to grow human sperm in the lab sometime in the future.”