These include the conditions related with azoospermia or oligozoospermia, such as Klinefelter's syndrome, Y chromosome deletions, Androgen receptor (AR) gene mutation, Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutation, genes related with isolated hypogonadotropic hypogonadism and genes defects found to be associated with reduced sperm motility and abnormal sperm morphology (Hotaling, 2014; Pereira et al., 2017; Krausz & Riera‐Escamilla, 2018). The gene discussed is CFTR; the disease is Klinefelter syndrome.