A

Turner-syndrome patients (45,X) have streak gonads with little or no estrogen production; because there is no Y-chromosome material, the risk of gonadal malignancy is minimal, so surgery is not required. The next step is estrogen replacement to induce secondary sexual characteristics and menstruation [Backeljauw & Klein, 2019, PMID 30809949; Hasegawa et al., 2023, PMID 37056677].