Koala (IMAGE) University of Queensland Caption "The koala is the only species in which a retrovirus is known to have recently infected the germline cells -- the ones that make sperm and eggs." -- Dr Keith Chappell Credit The University of Queensland Usage Restrictions To be only used with this story. 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.