Assisted Reproduction is a specialty undergoing rapid change as new technologies are introduced and new research challenges previous treatment options. This text examines a selection of controversial topics for both laboratory and clinical practice and tries to place them in perspective, so readers can understand how and why the current state of the question has come about and how future contributions to the debate should be measured. All physicians involved with the technologies concerned will learn from the expert contributions assembled here.CONTENTS: The use of ovarian markers * Use of molecular markers of endometrial receptivity * Use of Gn RHa for triggering final oocyte maturation during ovarian stimulation cycles * Use of time-lapse embryo imaging in assisted reproductive technology practice * Use of cryopreservation for all embryos * Preimplantation genetic screening * The use of single embryo transfer * Use of luteal phase support * Measuring safety and efficiency in in vitro fertilization * To flush follicles during egg collection or not * Use of blastocyst culture * Use of mitochondrial donation * Controversies in recurrent implantation failure: From theory to practice * Fibroids: To remove or not? * Limitations of endometrioma surgery in in vitro fertilization: Possibilities of early disease control