Abantu be-Intersex ngabantu abazalwa benanoma yiziphi izici zobulili ezibandakanya amaphethini we- chromosome , ama-gonads, noma izitho zangasese, ngokusho kwe- Office of the United Nations High Commissioner for Human Rights, "ezingahambelani nemibono kanambambili yemizimba yabesilisa noma yabesifazane". Yize ububanzi bezici zobulili ezingathandeki bungahle bube sobala kusukela ekuzalweni ngokutholakala kwezitho zangasese eziyindida, kwezinye izimo, izici ezi-atypical zingase zinganakwa, ziveze njengezitho zangaphakathi zokuzala noma ama-chromosomes angama-atypical angahlala engaziwa kumuntu impilo yabo yonke. Ukunikezwa kocansi ngesikhathi sokuzalwa kuvame ukuhambisana nobulili bengane yokwakheka kanye ne- phenotype . Isibalo sabantwana abazalwa benesitho sangasese esingaqondakali sisebangeni lika-0.02% kuya ku-0.05%. Ezinye izimo zibandakanya ama-chromosomes angama-atypical, ama-gonads, noma ama-hormone. Abanye abantu bangabelwa futhi bakhuliswe njengentombazane noma umfana kepha bese bezibandakanya nobunye ubulili kamuva empilweni, ngenkathi iningi liqhubeka nokuzibandakanya nobulili obabelwe. Isibalo sokuzalwa lapho ingane i-intersex ibikwe ngokuhlukile kuye ngokuthi ngubani obikayo nokuthi iyiphi incazelo ye-intersex esetshenziswayo. U-Anne Fausto-Sterling nababhali asebenza nabo basikisela ukuthi ukwanda kokuthuthuka kwezocansi okungenangqondo - kungahle kube ngaphezulu kuka-1.7%, kufaka phakathi nezimo odokotela abangaziboni njenge-intersex.