Gonadoblastomas are rare mixed gonadal tumors that are almost always found in individuals with 46, XY karyotype or some other form of Y chromosome mosaicism. It is extremely rare to diagnose gonadoblastoma in phenotypically normal 46, XX females. Herein, we present a 20-year-old 46, XX female diagnosed with gonadoblastoma and dysgerminoma. Use of cytogenetic and molecular analyses to identify the presence of Y chromosome material in peripheral blood, gonadal, and tumor tissue can exclude mosaicism to provide reassurance to undertake conservative surgical management and preserve fertility.