CFTR and cystic fibrosis: Infertility caused by obstructive azoospermia is observed in more than 95% of the males with cystic fibrosis, while 60-70% of the patients with CBAVD have mutations on the CFTR gene without manifesting clinical symptoms of cystic fibrosis (Asero et al., 2014; Claustres et al., 2000).