Gruber N, Kugler S, de Vries L, et al. - In this nationwide study, researchers examined the current incidence and the distribution of etiologies of primary ovarian insufficiency (POI). Recent data inscribed an increase in the prevalence of POI in young adult women but there is a lack of recent data cited for adolescents. All the pediatric endocrinology units in Israel provided data concerning females (aged < 21 years) diagnosed with POI during the years 2000–2016. They identified 130 females aged < 21 years for inclusion in the study; the distribution of POI etiologies was Turner syndrome/mosaicism in 56 (43%), idiopathic in 35 (27%), and other (developmental, genetic, metabolic, adrenal, and autoimmune) in 39 (30%) females. Observations suggest that in youth aged < 21 years, the incidence rate of POI was one-tenth of the rate that is generally cited. The rate of POI increased significantly in non-Turner females over the last decade. Contributions of environmental and epigenetic factors should be studied.