Allergic reaction to seminal plasma was described decades ago. In USA, only tens of thousands women are estimated to be affected. Not only seminal plasma but also cervicovaginal fluid contains sex-restricted antigens, yet allergy to cervicovaginal fluid has never been reported in medical literature. We came to a suspicion that because immunologic tests required to prove such a diagnosis, allergy to cervicovaginal fluid has never been reported yet it is not uncommon. The objective of this study was to use an Internet-based questionnaire to characterize the population of men with suspected hypersensitivity to cervicovaginal fluid. A questionnaire designed to cover localized and systemic symptoms of hypersensitivity reaction was made available via the Internet. Respondents with postcoital adverse reactions were invited to participate. Only respondents who presented with at least two symptoms suggestive to hypersensitivity to seminal plasma or cervicovaginal fluid and were negative for STI, and known hypersensitivity reactions such as latex allergy were a subject for further analysis. Board-certified dermatologists were surveyed for seeing bona fide cases of cervicovaginal fluid hypersensitivity. We have identified 52 cases of suspected hypersensitivity to cervicovaginal fluid (CVF). Both localized and systemic types of hypersensitivity were identified. A substantial number of dermatologists admitted to witnessing cases of hypersensitivity to CVF. Based on data from affected individuals as well as the opinions of dermatologists worldwide, we believe that allergic reaction to cervicovaginal fluid is at least as common as seminal plasma allergy. However, remains unreported due to technical difficulties in diagnosis and dermatologists' disbelief in its actual existence.