In 1946, Seckel collected from the literature 612 cases of sexual precocity and classified them according to their causes. Such tabulations do not give an accurate idea of the relative frequency of the different types, because more unusual cases caused by comparatively rare tumors of the ovary or testis are usually reported, whereas the numerous cases of idiopathic or cerebral type do not appear in the literature. In 1955, Jolly reported 69 cases of sexual precocity which he was able to locate throughout England and study personally. Wilkins, in 1957, published 94 cases studied in the previous 20 years in one pediatric endocrine clinic in the United States.
In his recent monograph entitled Precocious Sexual Development, Thamdrup has reported all cases which he was able to find in Denmark after studying all hospital records in that country and examining personally children under 8 or 9 years of age in 7