Genetic causes for infertility are not very common. However in cases of Kleinefelter, Turner or 47,XXX syndromes or specific types of chromosomal translocations, chromosomal abnormality may be the main factor of male or female infertility. Furthermore, CBAVD – congenital bilateral absence of the vas deferens is a condition were the patient is missing one or both vas deferens which connect the testicles to the penis,it is associated with a mild (usually undiagnosed) form of cystic fibrosis and occurs because of a mutation in the CFTR gene. Men with bilateral CBAVB, while able to create sperm, they are unable to transport it and as a result they are azoospermic, which means that their semen does not contain sperm. Finally, Microdeletions of the Y chromosome are found in more than 10% of men suffering from oligo- or azoospermia.