Complete hydatidiform mole and partial hydatidiform mole are two abnormal conceptuses that may be identified by clinical, ultrasonographic, gross morphological, histological, and genetic characteristics. Among all these criteria, the specific diagnosis is generally confirmed only upon histological review. However, an accurate diagnosis based on morphological criteria is difficult and several studies have shown that misclassifications are frequent, even for experienced pathologists. An erroneous diagnosis may imply that women are either not enrolled in an adequate beta-hCG follow-up with the risk that hydatidiform mole (HM) progresses to choriocarcinoma, or are enrolled in an unnecessary follow-up. A reliable and complementary method to the pathologic interpretation is a genetic study of the conceptus to eliminate the diagnostic dilemma by distinguishing non-molar spontaneous abortions from HM and to define the type of HM. The aim of our study was to review the genetic basis of HM and discuss its relevance in the routine management of the disorder.