Common examples include congenital bilateral absence of the vas deferens (CBAVD), which is associated with cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations, ejaculatory duct obstruction and/or cysts, seminal vesical atresia, idiopathic epididymal obstruction, genitourinary infections resulting in obstruction, and iatrogenic obstruction from vasectomy or other pelvic/inguinal surgery [9,10]. The gene discussed is CFTR; the disease is congenital bilateral aplasia of vas deferens from CFTR mutation.