Precocious puberty is one of the most common conditions encountered in the pediatric endocrinology clinic and can be defined as the appearance of secondary sexual characteristics in girls under 8 years and boys under 9 years of age. The timing of pubertal onset has received increasing attention because of a reported gradual decline in age at menarche in most populations. Proposed mechanisms for these changes include: an improvement in socioeconomic conditions with consequent increased nutritional status and a rise in a number of environmental pollutants. The challenges for pediatric endocrinologists are increasing: what are the mechanisms of precocious puberty in modern society? Should our diagnostic criteria be changed? When to treat? What are the consequences of treatment? Little is known of the short and long term consequences of GnRH-analog treatment, especially in terms of psychological consequences for children and their families.