The genetic basis of hydatidiform moles is well established, with each subtype exhibiting a specific genetic composition. These genetic signatures form the foundation for the molecular diagnosis and subtyping of hydatidiform moles in clinical practice. DNA genotyping through polymerase chain reaction (PCR) analysis of short-tandem repeat (STR) polymorphisms has become a powerful ancillary tool that enables precise pathological diagnosis and genotypical classification of different hydatidiform mole types. Beyond hydatidiform moles, STR genotyping has significant applications in the assessment of gestational trophoblastic tumors (GTTs). The detection of a distinct paternal genetic profile using STR analysis allows for the differentiation of GTTs from their non-gestational mimics, whether of germ cell or somatic origin. Additionally, STR genotyping can identify the causative gestation (e.g., term pregnancy, molar gestation, or non-molar abortion) associated with the development of GTTs, thereby determining the time interval for tumor development, which is crucial for FIGO/WHO prognostic risk scoring. Since 2008, numerous studies have validated the clinical sensitivity and specificity of STR genotyping in the diagnostic workup of gestational trophoblastic disease (GTD). As a result, its utility has been endorsed by both the WHO and the International Collaboration on Cancer Reporting (ICCR).