male sterilization

Last reviewed 01/2018

Vasectomy is a surgical procedure used to produce male sterilisation. It is a relatively simple procedure performed under local anaesthetic and associated with minimal morbidity.

The vas deferens is identified at the top of the scrotum by palpation and separated from adjacent blood vessels. Part or all of it is then excised

The patient must be warned that sterility is not immediate and that other forms of contraception should be employed until the ejaculate is confirmed to be sperm free.

Two negative specimens, starting three months after the operation and taken one month apart, are recommended before certifying that the patient is sterile. With these precautions, less than 1 in 1000 sterilisations fail. This is usually the result of recanalisation of the vas (1).

However, DNA-qualified fatherhood has occurred in the absence of clinically-detectable spermatozoa within semen (2).


  • Journal of Clinical Epidemiology (1993), 46, 697-927.
  • Smith, J.C., Cranston, D., et al., (1994). Fatherhood without apparent spermatozoa after vasectomy. Lancet; 344: 30.