Sperm Attach to Egg (image) Rockefeller University Press Caption Sperm (blue) latch onto a control egg (left) but can't bind to an egg lacking the glycoprotein ZP2 (right). Credit Avella et al., 2014 Usage Restrictions Reporters may freely use these materials in news coverage, with the appropriate credit information. 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.