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Can STIs cause male infertility?

Illustration of a fetus in womb

Men are responsible for about 20-30% of infertility cases — could the rise of STDs be causing these numbers? 

If you and your partner are struggling to have a baby, just know you are not alone. Many people usually think that infertility is a problem only faced by women, but the reality is that male infertility is more common than you think. Generally, infertility is defined as the inability to conceive a baby naturally. If you and your partner have been trying to have a baby for more than a year without success, you might want to speak to your doctor to discuss infertility.

According to the World Health Organization, male infertility is largely underestimated, and that infertility, in general, affects many people across the globe. While there is a lack of concrete data worldwide, researchers strongly believe that men alone are responsible for nearly 20-30% of infertility cases, and contribute to about half of all cases overall.

While there are numerous potential causes of infertility in men, including overall health, genetics and drug abuse, the latest evidence tends to suggest that sexually transmitted diseases, or simply STDs, have a role to play in male infertility.

How do sexually transmitted infections cause infertility in men?

First and foremost, it is worth noting that the extent to which STIs impact male fertility largely depends on the prevalence of these infections in a population. To be more precise, in the developed parts of the world, sexually transmitted diseases only play a minor role in impairing male fertility. However, in South East Asia or Africa, the situation appears to be different 

The structures of the male reproductive tract, including the urethra and epididymis, can be damaged by infections caused by untreated sexually transmitted infections. What's more, viral infections as well as immunodeficiency caused by HIV can impact the quality of semen fertility in men, making it harder for you and your partner to get pregnant.

For the most part, sexually transmitted infections affect sperm transport through infection and subsequent damage to the reproductive tract through which sperm travel but not through spermatogenesis which is the production process of the sperm in your testes. However, recent research suggests that chlamydia and Trichomonas vaginalis can potentially impair sperm production. 

Bearing in mind that most of these STIs are usually asymptomatic and quite difficult to diagnose, it is always likely that their role in male fertility is underestimated.

Picture of a man covering his crotch area

What sexually transmitted diseases are more likely to cause male fertility?


Chlamydia is the most common sexually transmitted infection that is curable. Because it rarely shows any symptoms in men, it can be hard to detect and treat. If left untreated, it can potentially lead to a significant decline in both the motility and quality of sperm, making conception difficult as a result.

Chlamydia is a bacterium, and usually infects the urethra in males. It affects not only your reproductive organs, but eyes and joints as well. Of course, you contract chlamydia by having unprotected sex with an infected partner. It is also important to note that chlamydia can be transmitted to newborn babies through a vaginal birth and cause conjunctivitis. Therefore, it is very important to ensure that as a man, you get tested before attempting conception. The good news is that chlamydia is easily treatable.


Gonorrhea is another sexually transmitted infection that can potentially cause infertility in men. Though not as common as chlamydia, it remains the common reportable sexually transmitted infection globally. Because gonorrhea can remain undetected for quite a long time, damage to the male reproductive tract is common. Like its chlamydia counterpart, gonorrhea can cause epididymis, which refers to the inflammation of the tube found in your testicles, which transports and preserves sperm. 

Gonorrhea can be easily treated using antibiotics. However, if left untreated, it can ultimately result in male infertility. Also important to note is that gonorrhea can be transmitted to the unborn child through vaginal delivery, causing gonococcal conjunctivitis which can lead to blindness.


Hepatitis is a general term used to describe liver inflammation and is usually split into a variety of types, including A, B, C, and D, among others. However, hepatitis B is the most common type that is linked with sexual transmission. Research shows that infertility is almost two times higher in patients with HBV infection compared to those without. This could be due to decreased sperm mobility of low sperm count caused by infection.

Genital herpes

While genital herpes has no effect on female fertility, herpes has been shown to cause fertility in males by reducing a man's sperm count. The bad news is that unlike the other types of sexually transmitted infections, genital herpes has no known cure. Symptoms such as blisters around the victim's genitals may appear and clear up by themselves, but the virus will permanently remain in your body and may cause blisters to outbreak at any moment.


Human Immunodeficiency disease is a deadly disease that is commonly transmitted from one person to another through body fluid or blood transfer and can cause Acquired Immunodeficiency Syndrome (AIDs). Like genital herpes, there is currently no cure for HIV, but there are numerous treatment options that can help control or manage the virus, allowing those already infected with the virus to live long and healthy lives.

As HIV breaks down your body's immune system over time, it also makes you highly vulnerable to other sexually transmitted infections such as gonorrhea and chlamydia, which could potentially cause male infertility. There is strong evidence that HIV can potentially lead to the loss of germ cells, which are the cells in the body that grow and develop in sperm in the testes, low testosterone as well as hypogonadism.

The bottom line

It is important to mention that a significant number of people infected with the above sexually transmitted infections will never become infertile! This is especially true for STI patients who are screened and subsequently treated appropriately. On most occasions, sexually transmitted infections that cause infertility in both men and women do so because of chronic and undetected infections.

When unnoticed and left untreated, some sexually transmitted diseases can potentially cause extensive damage to your reproductive tract, leading to infertility. This is why regular STI screening is very important because it helps identify asymptomatic infections. If the tests show that you have any sexually transmitted infection, you should seek appropriate treatment immediately. Treatment options for STIs in Singapore are usually very simple yet highly effective, so you should never feel discouraged when it comes to planning your future family!


  1. Ochsendorf F. R. (2008). Sexually transmitted infections: impact on male fertility. Andrologia, 40(2), 72–75. https://doi.org/10.1111/j.1439-0272.2007.00825.x
  2. Abdulmedzhidova, A. G., Kurilo, L. F., Shileĭko, L. V., Makarova, N. P., Klimova, R. R., & Kushch, A. A. (2007). Urologiia (Moscow, Russia : 1999), (3), 56–59.
  3. Liu, W., Han, R., Wu, H., & Han, D. (2018). Viral threat to male fertility. Andrologia, 50(11), e13140. https://doi.org/10.1111/and.13140

This article was written and medically reviewed by Dr Ben, M.D on 27/08/21

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