The aims of this study are: 1) to identify genes that play a role in human pubertal development and reproduction, 2) to characterize the phenotypic spectrum of patients with these gene defects, and 3) to discern the mode of inheritance for disorders caused by these gene defects. We are specifically interested in genes that cause Kallmann syndrome, idiopathic hypogonadotropic hypogonadism (IHH), precocious (early) puberty, and delayed puberty. Individuals do not have to travel to Boston to participate in this study.