Qualitative spermatogenic defects or ductal obstruction usually manifest as azoospermia, and multiple genetic factors are validated as the causes, including numerical and structural chromosomal anomalies (e.g., Klinefelter’s syndrome, 46, XX male syndrome), Y-chromosome micro-deletions (e.g., azoospermia factor (AZF) deletions), gene mutations (e.g., TEX11 deletions), and cystic fibrosis transmembrane conductance regulator (CFTR) mutations (Krausz and Riera-Escamilla, 2018). The gene discussed is CFTR; the disease is Azoospermia.