The current proposal involves a cross-sectional and longitudinal study design which will address the current specific aims: 1) to demonstrate that the magnitude of impairment in GnRH secretion, as determined by the dynamic pattern of gonadotropin and ovarian steroid secretion across the normal menstrual cycle, is positively correlated with increasing severity of dieting behavior; 2) to demonstrate that persistent dieting behavior is an important mediating factor in the development of impaired GnRH secretion, and 3) to examine the role of dieting-associated behavioral distress in the development of impaired GnRH secretion. While the exact mechanisms of dieting-induced ovulatory failure remain to be determined, a more thorough characterization of this process will help in earlier recognition of the problem and the development of more specific strategies for intervention. Such approaches may, in turn, diminish the incidence of infertility associated with chronic ovulatory failure.