Does urinating after sex prevent catching HIV or other infections?

An infectious rumour

Also in this week's column:

Does urinating after sex prevent catching HIV or other infections?

Asked by John Norton of Philadelphia, USA

It is widely believed that urinating after sex will prevent sexually transmitted diseases such as HIV. However, this is a myth, say medical experts.

According to Dr Basil Donovan of the National Centre in HIV Epidemiology and Clinical Research of the University of New South Wales in Australia, this notion "is a widely held belief among soldiers", but "has never been clinically proven". He adds that this idea is merely "part of the rich area of sexual myth".

HIV is transmitted via bodily fluids. Welcome back from the planet Neptune if you do not know how to prevent HIV during sexual activity!

Another myth is that the partner on top during intercourse will not catch a sexually transmitted disease. Dr Donovan notes that "some people believe infections are gravity-fed or that quick withdrawal prevents transmission. The danger of believing in and following practices based on these myths is that people may not be adequately protected against diseases, some of which are life-threatening".

It is also not proven that urinating after intercourse helps prevent a woman from getting a urinary tract infection. The theory here is that the woman should urinate soon after intercourse so that any bacteria that might possibly get into the urinary tract will be flushed out. But the theory may be dangerous to rely upon in practice. If a urinary tract infection occurs, it can eventually spread into the kidneys which can cause a kidney infection (pyelonephritis) and major problems.

Much of the above is beyond the competence of an anthropologist writing about body, brain, and behaviour. Yet another myth is that urinating after sexual intercourse will prevent pregnancy. Absolutely not! This is according to the website of Planned Parenthood Federation of America in New York City. Consult your family physician with any personal questions in this area, especially if you are confused or have spent too long on planet Neptune.

Stephen Juan, Ph.D. is an anthropologist at the University of Sydney. Email your Odd Body questions to s.juan@edfac.usyd.edu.au

Sponsored: 10 ways wire data helps conquer IT complexity