Vulvodynia (VD) is a chronic pain disorder affecting up to 15% of women and resulting in substantial impairment in health-related quality-of-life. The treatment of the disorder is hampered by a lack of knowledge regarding its neurobiological basis. The proposed study is based on the general hypothesis that like other persistent pain conditions, VD clinical phenotypes (characteristic of the disorder) are composed of multiple biological endophenotypes (such as an hereditary characteristic that is normally associated with a condition but not a direct symptom of that condition) and that meaningful subgroups can be identified.