Sperm health - avoiding STIsA healthy male produces millions of sperm each day, although only a few of these sperm will ever go on to fertilise an egg and create an embryo. Despite the vast quantity of sperm produced by a healthy man, the number of sperm which actually fulfil their fertilising potential is therefore extremely small. Even when a man is producing sperm at a healthy capacity and his partner is fertile, it is not uncommon for couples to take up to a year to conceive.

Some men produce sperm which is suboptimal, either in quantity or quality. These men will typically take longer to conceive and are more likely to require the assistance of artificial reproduction techniques to do so. Some men may experience suboptimal sperm production because of a genetic or birth trait (e.g. deletions on the Y chromosome or history of cryptorchidism). In many cases, sperm production declines over time as a result of exposure to a range of risk factors.

Sexually Transmitted Infection (STIs) have a range of negative health affects. In males, one effect of STIs is reduced fertility. Avoiding STIs is therefore an important measure men can take to maintain optimal sperm production and maximise their chances of conception.

How sexually transmitted infections affect sperm health

The extent to which sexually transmitted infections impact on male fertility depends on the prevalence of these infections in the population. In developed countries, STIs play only a minor role in impairing male fertility.

For the most part, STIs affect sperm transport (e.g. by causing infection and subsequent damage to the testicular tubes through which sperm travel) rather than spermatogenesis (the production of sperm in the testes). There is however evidence that the STIs Ureaplasma urealyticum, Trichomonas vaginalis and Chlamydia Trachomanis all impair sperm production. As these STis are often asymptomatic and can be difficult to diagnose, it is likely that their contribution to male infertility is underestimated.

The ways in which impaired sperm production related to STIs is an area that requires further research. However, a number of hypotheses have been put forward. Laboratory studies have shown that some bacteria impair sperm motility and viability, and it is possible that the bacteria which cause STIs also impair sperm in these ways. Chronic inflammatory conditions (untreated STIs are considered chronic inflammatory conditions) are associated with sub optimal sperm function. Infections of the genital tract may cause damage to the testes. There is also some evidence that the production of antisperm antibodies in the genital tract increase in response to infection, and increased anti-sperm antibodies are associated with decreased semen parameters.

Human Immunodeficiency Virus (HIV) also impacts on sperm production and semen parameters deteriorate as immunodeficiency progresses. For example, one recent study reported decreased concentrations of motile sperm in HIV+ compared to HIV- men. The ways in which HIV is related to male sub-fertility is also unclear. It may be associated with decreased immune function, the effects of anti retroviral therapy medication, or co-existing genito-urinary tract infection.

Keeping sperm healthy: avoiding sexually transmitted infections

Sperm health - avoiding STIsSTIs, as the name suggests are spread through sexual contact. The two main ways individuals can avoid STIs are by avoiding sexual activity, or using a male or female condom to prevent the mixing of sexual fluids which transmit STIs, during intercourse. Individuals who do not use condoms consistently should be tested for STIs such as Chlamydia, which are typically asymptomatic and may therefore only be diagnosed if laboratory tests are conducted.

Individuals who do not manage to avoid STIs should seek prompt treatment. Many STIs can be treated quickly and easily using antibiotics. Prompt treatment can limit damage to the male reproductive system and its negative effects on sperm production and transport.


More information

Semen analysis


For more information on sperm health and male fertility, see Sperm Health


Sexually transmitted infections (STIs)
For more information on different types of sexually transmitted infections, prevention of STIs, treatments and effects on fertility, see Sexually transmitted infections (STIs).



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