Endometriosis is a chronic disease characterized by the presence of functional endometrial glands and stroma in ectopic locations outside the uterine cavity. The ectopic endometrial tissue responds to estradiol and other hormones similarly to the normal endometrium. Endometriosis is one of the most common benign gynecological conditions, as many as 5-10% of women in the reproductive age may be affected. In addition to pain which may be severe, subfertility is one of the typical problems associated with endometriosis and may be present in up to 40% of those affected. There is lack of a clear correlation between severity of pain and degree of compromised fertility. Different modes of treatment exist. Hormonal treatments are based on the suppression of estrogenic action on endometriosis as well as the endometrium. Unfortunately, discontinuation of the hormonal treatment typically results in a rapid recurrence of the disease. Surgery may alleviate the symptom for different lengths of time, however, curative treatment frequently involves hysterectomy with bilateral oophorectomy. In order to escape this radical treatment, new targeted therapy in the form of novel pharmacological agents would be of crucial importance. Presently, endometriosis can be reliably diagnosed only by laparoscopy. Since this is an invasive surgical procedure, new diagnostic tools would be warmly welcomed. Furthermore, as the progression of the disease is presently impossible to predict, new markers for the malignancy of each case are desperately needed. The aim of the investigators research is to identify expression of endometriosis specific RNAs/proteins. Evaluation of expression profiles in samples of endometriosis and endometrium of patients with careful clinical and surgical classification of endometriosis as well as healthy control women should initially enable to identify novel targets for new therapies and biomarkers. Particularly the different pain symptoms will be recorded annually and evaluated comprehensively. Furthermore, combined with an adequate 10-year follow up (based on a questionnaire, including fertility, received treatments and different pain symptoms; NRS), the study should enable for example to identify markers for endometriosis associated infertility as well as cases where the disease progresses very rapidly or reoccurs. Different forms of effective treatment may thereafter be designed following the identification of such factors.