normal and abnormal sperms (IMAGE) University of Gothenburg Caption It was found that male mice with no ability to produce the MC2 protein were unable to form the connection between the tail and the head of the sperm and the mice became infertile. The microscope images clearly show the difference in the sperm. Credit Kexin Zhang Usage Restrictions None License Original 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.