The vas deferens is part of the male reproductive system in mammals. Each of the pair of tubes possesses strong muscles that are utilized to transport sperm from the testes to the urethra.
A congenital bilateral absence of the vas deferens ((CBAVD)) is sometimes an underlying cause of sterility in men. Certain techniques, however, have been developed that enable men having the condition to father children. Yet, the advisability of assisted reproduction in such cases is questionable. Scientists have genetically linked the condition to another disease, and men with CBAVD are believed to be more likely to produce children with cystic fibrosis.
When a man elects to have a vasectomy, each of his vas deferens is surgically affected. During the male sterilization process, two small incisions allow a physician to sever and then seal each tube. The relatively simple procedure is sometimes performed to help prevent infections rather than to inhibit reproduction and is generally considered permanent. However, the process can sometimes be reversed and success rates are likely to improve with further advances in microsurgery.