Precocious puberty may be due to organic lesions on the hypothalamus which are primarily tumors or it may be idiopathic in nature. The purpose of this project is to determine whether MRI is a useful method in separating these two groups. If so, it will be interesting to know whether it is an advantageous method as compared to CT. In addition, this study is undertaken to determine whether MRI can separate the different kind of tumors responsible for this condition.