Atypical formation of the gonads early in gestation. In complete gonadal dysgenesis, the gonads don’t function at all, resulting in female genitalia. In partial gonadal dysgenesis, the testes function, but not at the same level as typical testes, resulting in ambiguous genitalia. In mixed gonadal dysgenesis, a streak gonad develops on one side, and a partially developed testis on the other side.