This Special Issue of the Journal of Clinical Medicine is dedicated to polycystic ovary syndrome (PCOS). It includes 12 interesting papers from all around the world that contribute important new information regarding the pathogenesis, clinical evaluation, and treatment of this very common disorder that affects about 10% of all women during their adult life.

The first paper presents an evolutionary model of PCOS that has profound consequences on the methods of preventing and treating this syndrome. Other papers describe problems related to differential diagnosis from hypothalamic amenorrhea and the use of questionnaires for detecting alterations in the quality of life of these women.

Two papers are dedicated to sexual problems that may arise in these patients. Many papers analyze the actual treatment of PCOS, from the promotion of physical activity to the use of oral versus intravaginal contraceptives.

Articles also investigate how to optimize the clomiphene induction of ovulation or to improve pregnancy outcomes. One paper analyzes the importance of hypoglycemia in determining the long-term effects of different diets.

Finally, two important papers report on the results of new treatments for high body weight in women with PCOS. .