Mouse Sperm (IMAGE) University of California - San Diego Caption In experimental mice, researchers found that sperm production is dramatically reduced when the NMD repressor, UPF3A, is prevented from being expressed in the cells that give rise to sperm. Credit UC San Diego Health Usage Restrictions Use photo credit as indicated License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.