Evolution (IMAGE) Université de Genève Caption From left to right are: genital ridge at the time of sex determination; fetal testis and seminiferous cords; fluorescent adult testis; cross-section of adult seminiferous tubule. Credit ©UNIGE, S. Nef's laboratory Usage Restrictions None 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.