A thin rubber or plastic sheath placed over the erect PENIS before sexual intercourse. It is the most effective type of barrier contraception and is also valuable in preventing the transfer between sexual partners of pathogenic organisms such as gonococci, which cause GONORRHOEA, and human immuno-deficiency virus, which may lead to AIDS (see AIDS/HIV). Sheaths are most effective when properly used and with spermicides.

The female condom might be suitable for contraception when a woman misses a day or two of her contraceptive pill; if there is DYSPAREUNIA; when the perineum needs protection, for example, after childbirth; or in cases of latex allergy to traditional condoms. Used properly with spermicide, it provides an effective barrier both to infections and to spermatozoa. Failure may result if the penis goes alongside the condom, if the condom gets pushed up into the vagina, or if it falls out. (See CONTRACEPTION.)