CBAVD: congenital bilateral absence of the vas deferens; CF: cystic fibrosis; CFTR: CF transmembrane conductance regulator; CNV: copy number variation; CVS: chorionic villus sampling; MLPA: multiplex ligation-dependent probe amplification; PGT-M: preimplantation genetic testing for monogenic conditions; ICSI: intracytoplasmic sperm injection. This evidence concerns the gene CFTR and cystic fibrosis.