The goal of CPP-EDG 01 study is to assess possible genetic and/or environmental parameters which may influence the growth rate of children affected by precocious puberty. In this view, we are collecting clinical data and biological samples of children attended as outpatients at the Pediatric Endocrine Center of Pisa from 1998 to present (the study is still open). From biological (blood) samples, gene polymorphisms such as endocrine disruptor levels are determined and compared to different growth pattern of pediatric patients treated with different GnRH agonists.