Is he likely to be HIV positive?

In most cases, when gay men have sex with someone new they will not know the HIV status of their partner. Most estimates suggest that between one in ten and one in eight gay men in London have been infected with HIV. Between a third and a quarter of these men have not been diagnosed and so probably do not know that they are HIV positive.

Even if we knew exactly what percentage of gay men are living with HIV it would not tell you what the actual chance is of you having sex with someone of a different HIV status. We do know that there are HIV positive men in every part of the UK and that there are HIV positive men of every age and nationality. Because of advances in treatment, it is becoming increasingly rare that someone shows visible signs of HIV infection, such as facial wasting or the skin cancer Kaposi's Sarcoma. The majority of men in the UK living with HIV will probably not have any visible symptoms and so you will no by able to tell by looking at them. It's easy to think that only a certain ‘type’ of gay man is likely to have HIV but this is not true. There are men on the extreme sex circuit who are HIV negative, just as there are HIV positive young guys dancing to Kylie at G–A–Y on a Saturday night. One HIV doctor recently commented, ‘The diverse mix of patients I see always amazes me. I treat the young, old, waiters, lawyers and even other doctors.’

It is unrealistic to expect someone to tell you their HIV status. According to the most recent data, about two-thirds of HIV negative gay men expect HIV positive men to disclose their status before sex. However data collected by GMFA, in a survey of positive men's attitudes and experience, shows that almost 40% of men living with HIV won't say that they're positive before sex. Another 40% of HIV positive men said that they sometimes told the men they had sex with that they were positive, and only 20% of them said they always disclosed their status.

This doesn't mean that HIV positive men are deliberately misleading their partners - just that many of them decide not to tell. This could be for a variety of reasons, such as an expectation that there will be no risk of transmission in the sex - or a fear of rejection.

So long as HIV is associated with stigma and fear, telling someone you're positive is likely to lead to rejection – and who wants to be rejected?

The fear of rejection is not unfounded. Research by Sigma in their annual Gay Men's Sex Survey found that almost half of HIV negative men would not want to have sex with a positive man. With so many HIV negative men rejecting men who disclose, it's not surprising that many positive men decide to keep quiet about their HIV status, especially if they're not expecting to have unsafe sex, or if they're in a situation where it's hard to talk.

Most gay men, whether they are HIV positive or HIV negative, have safer sex most of the time. Because they expect that the sex will be safe, many HIV positive men won't disclose their status because they don't think it's relevant. At other times and in other places, for example saunas and backrooms where conversation isn't expected, it's difficult for a positive man to find a way to talk about his status, even if he wants to. In these situations it's likely that an HIV negative man won't reveal his status, even if he's about to have unprotected sex with a stranger.

Many HIV negative men tend to think that if someone is willing to have unprotected sex with them, they will also be HIV negative. And many HIV positive men believe that if someone is willing to have unprotected sex with them, it's because they are also HIV positive. This is how HIV is often transmitted. If someone you're going to have sex with doesn't mention HIV, it doesn't necessarily mean that he's HIV negative or that he's HIV positive, it just means he's not chosen to talk about it.

Another reason why a positive man may not reveal his HIV status is that he may not know that he is HIV positive. It is estimated that between a third and a quarter of HIV positive gay men in the UK have not been tested since they were infected, and many of these men will believe that they are still HIV negative.

If everyone only had sex with people who had the same HIV status then there would be no increase in the number of people living with HIV. Sero-sorting is the name given to the practise of selecting partners with the same HIV status (i.e. HIV positive men only sleep with other HIV positive men, HIV negative men only sleep with other HIV negative men). Many HIV positive men use online dating sites, such as gaydar, to find other HIV positive men for condomless sex, because they feel more able to disclose online (although many positive men still won't choose to give out that information about themselves).

If you're HIV negative and only have sex with other HIV negative men then you won't catch HIV from sex, although you still risk catching other STIs . The challenge is to be sure that the men you have sex with really are HIV negative. If you are sexually active and have taken even small risks in the past, the only way to be sure of your status is to have an HIV test. The HIV test is only able to tell you whether you have developed antibodies to the virus, and these can take up to three months after infection before they show on the test. For this reason, it's not sensible to have unprotected sex with someone you've just met on the basis that they say they're HIV negative. If they're willing to take that risk with you, they're probably willing to take that risk with other people too and it's possible that they're HIV positive but don't know it.

The fact that there have been prosecutions for transmission of HIV does not mean that HIV negative men can assume that they are not at risk. So long as there are HIV positive men who are unaware of their status, there will always be positive men who will not disclose their status. Even if all positive men were aware of their status, it's likely that many men, for a variety of reasons, will choose not to disclose their status before sex.