aDepartment of Obstetrics and Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut

bInnovation Institute for Fertility Preservation, New York and CT, USA

cDepartment of Obstetrics and Gynecology, Istanbul Health and Technology University School of Medicine, Istanbul, Turkey

Correspondence to Kutluk H. Oktay, MD, PhD, FACOG, Yale School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA. Tel: +1 203 785 4452; e-mail: [email protected]