Knowledge of human genetics has increased dramatically, and obstetrician–gynecologists and other health care providers are increasingly called on to incorporate genetics and genetic testing into medical practice. Advances in our understanding of the molecular basis of inherited disorders have led to the development of DNA-based tests that can be used for prenatal and postnatal diagnosis, carrier testing, and aneuploidy screening. These techniques have allowed for diagnosis of a wide variety of genetic diseases ranging from aneuploidies to single-gene disorders. Once a specific pathogenic variant in a gene has been identified, direct testing for that specific variant is possible; this is the most accurate molecular diagnostic method. Counseling patients about genetic testing and results can be challenging and obstetrician–gynecologists and women’s health care providers are encouraged to make use of and refer to genetics professionals when necessary. The correct interpretation of molecular genetic diagnostic testing is highly dependent on an accurate clinical diagnosis, test sensitivity, ethnic variability in variants and disease prevalence, genetic heterogeneity, reduced penetrance, and phenotypical variability. As genetics becomes a more integral part of routine medical practice, it is essential that obstetrician–gynecologists and other health care providers be aware of advances in the understanding of genetic disease and the fundamental principles of genetic screening and molecular testing. This technology assessment has been revised to reflect advances in clinical genetics related to obstetrics and gynecology, including epigenetics, sequencing, and testing.