"Sperm Book" (IMAGE) Cell Press Caption This photo shows how a sperm sheet of hundred or thousand of mouse strains can be preserve only one card-holder or “sperm book”. It is very easy to handle. This method also reduces the risk of failure to preserve, preservation costs, and space requirements. Credit Daiyu Ito, University of Yamanashi Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. Adaptations must be shared under the same terms. License CC BY-NC-SA 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.