Final answer:
Genetic testing for Huntington's Disease is usually conducted after symptoms manifest. PGD can diagnose conditions like sickle cell anemia and Down's syndrome but not sexually transmitted diseases. The FDA can intervene at various stages of gene therapy approval.
Step-by-step explanation:
Exclusionary genetic testing for Huntington's Disease (HD) is typically performed after the onset of symptoms, rather than at birth, during pregnancy, or before marriage. Prenatal genetic diagnosis (PGD) is commonly used to detect certain genetic conditions before an embryo is implanted. Conditions like sickle cell anemia, Down's syndrome, and sex determination can be diagnosed using PGD.
However, inheritance of sexually transmitted diseases cannot be diagnosed by PGD. Genetic disorders like Huntington's Disease can be identified through hereditary diseases carrier diagnosis. Yet, the decision to conduct genetic testing involves various ethical considerations and the procedure's financial cost.
Risk factors such as age play a significant role in the likelihood of having a child with Down syndrome, emphasizing the importance of genetic counseling in understanding these risks. During the process of approving gene therapy, the FDA may intervene at multiple points, such as submission of an IND application, during clinical trials, or after the manufacturing and marketing of approved therapies.