CFTR and male infertility: Cystic fibrosis (CF) is one of the most frequent life-limiting autosomal recessive diseases, characterized in its classical form by chronic pulmonary obstruction and infections, pancreatic insufficiency, male infertility, sweat chloride concentrations ≥60 mmol/L and two loss-of-function variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene (NM_000492.4; LRG_663t1) [1].