We are continuing to explore the effect of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in relation to the diagnosis of endometriosis, particularly in the context of lifestyle behaviors. Much of our effort to date has focused on PCBs. Our current analyses are focusing on OCPs and the development of endometriosis. Again, our focus is chemical exposure in the context of lifestyle, given that many lifestyle behaviors utilize similiar enzymatic pathways for clearance. This work was designed to guide the development of the analytic plan for the ENDO Study.