is a full Professor at Luebeck University, Germany, and chair at the Department of Gynecological Endocrinology and Reproductive Medicine, University Hospital of Schleswig-Holstein, Luebeck, Germany. He trained at the University of Vienna, where he worked in trophoblast research for his MD thesis at the Department of Obstetrics, and then did postdoctoral studies at University College London, where he obtained an MSc in prenatal genetics and fetal medicine. His PhD was on ovarian stimulation for IVF using GnRH-antagonists. His research interests include the endocrinology of ovarian stimulation, evidence-based medicine in reproductive health care, epidemiological studies in IVF, preimplantation genetic diagnosis, and basic aspects of folliculogenesis and cryopreservation of human ovarian tissue. He has been an Associate Editor for Human Reproduction 2008-2012, for Fertility and Sterility 2010-2012, and for the British Journal of Obstetrics and Gynecology 2013-2016. He is currently section editor for Reproductive Biomedicine Online and editor in-chief at Gynaekologische Endokrinologie. Furthermore, he is past coordinator of the special interest group REPRODUCTIVE ENDOCRINOLOGY of the ESHRE and served on the Executive Committee of the ESHRE from 2013-2017.