Having unprotected penetrative sex is the most likely way to pass on a sexually transmitted infection (STI). Using a condom helps protect against HIV and lowers the risk of getting many other STIs.

A survey of gay and bisexual men by Stonewall revealed that 1 in 3 men had never had an HIV test, and 1 in 4 had never been tested for any STI. Men who have sex with men (MSM) should have a check-up at least every 6 months at a sexual health or genitourinary medicine (GUM) clinic. This is important, as some STIs do not cause any symptoms.

Hepatitis A

Hepatitis A is a liver infection that's spread by a virus in poo. The infection is usually spread in contaminated food or drink, or by poor hand-washing. However you can also get hepatitis A through sex, including oral-anal sex ("rimming") and giving oral sex after anal sex. MSM with multiple partners are particularly at risk.

Symptoms of hepatitis A can appear up to 8 weeks after sex and include tiredness and feeling sick (nausea). Hepatitis A is not usually life-threatening and most people make a full recovery within a couple of months.

MSM can avoid getting hepatitis A by:

• washing hands after sex (bottom, groin and penis too by taking a shower, if you can)
• changing condoms between anal and oral sex
• using a barrier (such as a condom cut into a square) for rimming
• using latex or non-latex gloves
• asking about the hepatitis A vaccine at a sexual health or GUM clinic

If you think you might have hepatitis A, or have any questions, visit a sexual health or GUM clinic. The hepatitis A vaccine is available for people travelling to countries where the disease is common.

Hepatitis B

Hepatitis B is a viral infection that causes inflammation of the liver. It does not usually cause obvious symptoms and may pass in a few months without treatment. However in some cases the infection can persist and cause serious liver disease, including cirrhosis and liver cancer.

Hepatitis B is spread through contact with the blood or body fluids of an infected person. MSM are at risk of hepatitis B but they can be protected by the hepatitis B vaccination.

Vaccination for MSM is available from sexual health clinics, genitourinary medicine (GUM) clinics or from GPs.

Hepatitis C

Hepatitis C is a viral infection that causes inflammation of the liver. It often does not cause any obvious symptoms at first, but it can lead to serious liver disease if left untreated.

It is spread through contact with the blood of an infected person. Men who are concerned they are at risk should consult their doctor or sexual health clinic. Hepatitis C can be treated and is curable in many cases.

Gonorrhoea

This bacterial infection causes stinging when you pee, or the feeling that you want to pee but are unable to. It's passed on through anal, oral or vaginal sex with an infected person.

Gonorrhoea is treated with antibiotics.

Non-specific urethritis (NSU)

This is inflammation of the urethra (the tube that carries urine from the bladder out of the body) caused by bacteria. It is also called non-gonococcal urethritis (NGU) when the condition is not caused by gonorrhoea.

NSU is passed on in the same way as gonorrhoea and often has similar symptoms. It can also be caused by having lots of sex or masturbating a lot, which can make the urethra inflamed. It can be treated with antibiotics.

Chlamydia

This is a bacterial infection of the urethra or bottom (rectum). It can also affect the throat, but this is less common. Chlamydia may cause a discharge, pain when you pee, or pain in the testicles. However, not everyone has symptoms.

It can be passed on during sex with an infected person in the same way as gonorrhoea. It's treated with antibiotics.

Genital herpes

Genital herpes is a viral infection. Symptoms can include painful blisters and ulcers on or around the penis or bottom (anus), although some men have no symptoms. The virus stays in the body and can cause outbreaks of blisters.

Genital herpes can be passed on through oral sex with someone who has a cold sore around or in their mouth, or by skin-to-skin genital contact with someone who has genital herpes.

Antiviral tablets and creams from a GP or sexual health clinic can help the symptoms.

Syphilis

Syphilis is a bacterial infection that causes a painless ulcer, usually in the genital area. The ulcer will disappear on its own but other symptoms may appear, such as a rash on the body and swollen glands.

In its early stages, syphilis is very infectious and can be passed on by close skin contact during sex. If you do not treat it, the infection can eventually spread to the brain or other parts of the body and cause serious, long-term problems. Treatment is with antibiotic injections or tablets.

Genital warts

This is a common viral infection caused by the human papillomavirus (HPV). It appears a few weeks or months after sex with an infected person. It can cause pinhead-size growths, mostly on or around the head of the penis but also in and around the bottom (anus).

The sooner warts are treated, the easier they are to manage. You cannot treat genital warts with the same type of cream you use for warts on other parts of your body. A doctor will freeze them or prescribe a cream to remove them.

You can reduce your risk of getting genital warts by getting the HPV vaccine. MSM up to and including the age of 45 become eligible for free HPV vaccination on the NHS when they visit a sexual health or HIV clinic in England.

Pubic lice

Public lice (also known as "crabs") are small, parasitic insects that live in body hair. They are very small (only 2mm), so they can be difficult to see, although their tiny dark eggs can be seen stuck to hair.

Pubic lice prefer the pubic hair around your testicles and bottom but may also be found in body hair. They are not found on your scalp.

The lice are spread through close bodily contact with an infected person. They can also be spread by sharing clothes, towels or bedding, but this is rare. Symptoms include itching or a rash.

Treatment can be done at home with lotions or creams bought from a pharmacy (no prescription is needed).

Scabies

This is an infection caused by tiny mites that burrow under the skin. It causes intense itching for most people (though some hardly notice it). Itching usually starts 2 or more weeks after sex with an infected person. You can also get scabies from sharing beds and towels, but this is less common.

Treatment is similar to treating pubic lice, although you may continue to itch for a few weeks after the mites have been removed.

Get tested

If you have any of the symptoms above or are worried you may have an STI, speak to your GP or visit a sexual health or GUM clinic. Getting tested regularly is a good way to ensure you have a healthy sex life. NHS services are free.