Endometriosis-Reply

In Reply.— Several issues about which Dr Redwine requests clarification were discussed in the text of our article. The cases in this study were selected from a broader study of infertility due to many different causes. Women with endometriosis formed a unique and definable group that was the subject of this report. The study design did not permit us to recruit women with other signs of endometriosis unless they also were infertile. Dr Redwine is correct that age is a potential confounding factor, but we recognized this and controlled for it by multivariate analysis. This means that the associations discussed held in groups of cases and controls who were the same age. All controls who said they had a clinical diagnosis of endometriosis were excluded. It was clearly not feasible to perform laparoscopy on the remaining controls to be certain that they did not have undiagnosed endometriosis. We do not