CFTR and cystic fibrosis: Considering that in CF patients, the CFTR protein involves in development of the epididymis and vas deferens, as well as in spermatogenesis, sperm maturation, luteinizing hormone, and testosterone levels [9,23,24,25,26], and also taking into account data about a higher CFTR mutation frequency in individuals with impaired sperm production or hypogonadism [24,25,29,58,59], a search for associations of pathogenic CFTR variants with semen quality and hormonal status was carried out in current study.