1. The vertebrate Balbiani body, germ plasm, and oocyte polarity Allison Jamieson-Lucy and Mary C. Mullins 2. Genetic basis for primordial germ cells specification in mouse and human: Conserved and divergent roles of PRDM and SOX transcription factors Anastasiya Sybirna, Frederick C.K. Wong and M. Azim Surani 3. Germ cell reprogramming Kazuki Kurimoto and Mitinori Saitou 4. From worm to germ: Germ cell development and regeneration in planarians Melanie Issigonis and Phillip A. Newmark 5. Heterogeneity of primordial germ cells Daniel H. Nguyen, Rebecca G. Jaszczak and Diana J. Laird 6. Germline stem cell homeostasis Jonathan O. Nelson, Cuie Chen and Yukiko Yamashita 7. Heterogeneous, dynamic, and stochastic nature of mammalian spermatogenic stem cells Shosei Yoshida 8. Sperm success and immunity Stuart Wigby, Susan S. Suarez, Brian P. Lazzaro, Tomaso Pizzari and Mariana F. Wolfner 9. A symbiont's guide to the germline Shelbi L Russell, Laura Chappell and William Sullivan