Currently, there is steadily increasing experimental evidence on the existence of pluripotent/multipotent stem cells in neonatal and adult mammalian ovaries, including humans. The ovarian stem cells seem to be present in the ovarian surface epithelium layer, in the ovarian cortex tissue, or as a subpopulation of granulosa cells in adult human ovaries. Recently, more articles have reported the presence of stem cell populations in the adult tissues of human endometrium and oviducts. The testicular tissues might be an important source of stem cells, from the in vitro proliferating and reprogrammed spermatogonia to the mesenchymal stem cells expressing some markers of pluripotency. The new approach–understanding of stem cells in reproductive tissues–is of enormous value in terms of gaining a better understanding of some gynecological diseases (e.g., premature ovarian failure and endometriosis), the manifestation of aggressive cancers, a potential gamete renewal, and potential use of reproductive tissues that are commonly thrown away in medical practice as an important source of stem cells for regenerative medicine. The new knowledge on stem cells in reproductive tissues might lead to better diagnostics and more advanced and individualized therapies of different diseases in the future.

The main focus of this special issue will be on the new and established findings with a goal to better understand some new aspects of stem cells in gonadal and other reproductive tissues in the animal models and in humans. The special issue will become an important international forum for researchers and have tendency to summarize the most recent and advanced developments, approaches, and ideas in the field. Potential topics include, but are not limited to:

• Stem cells in fetal and adult ovaries
• Stem cells in fetal and adult testicles
• Spermatogonial stem cells
• Endometrial stem cells
• Stem cells in menstrual blood
• Stem cells in oviducts
• Primordial germ cells
• Cancer stem cells
• Stem cell basics
• Stem cell research, diagnostics, and treatment
• In vitro gametogenesis

Before submission authors should carefully read over the journal's Author Guidelines, which are located at http://www.hindawi.com/journals/jbb/guidelines/. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/ according to the following timetable: