Although this question is framed in a heterosexist way, the same question can just as well apply to gay men, although there is more of a (possibly incorrect) assumption that in gay male relationships sexual roles are more fluid and the power to enforce condom use is more equally shared between the two partners.

However we find that in gay men the same pattern applies as among heterosexuals, and this gives us a clue as to the primary psychological driver behind unsafe sex and the decision to use, or not to use, condoms. In general, men in steady relationships, whether of the same HIV status or not, are far less likely to use condoms.

Take two examples. A study from the Netherlands (Davidovich 2000) found that 55 per cent of gay men had unprotected sex with their regular partner but only 20 per cent had it with casual partners.

A London study (Elford 2001) a year later stratified the same results by HIV status of participants. It found that in HIV negative men 28.5 per cent had unprotected sex within relationships but only five per cent with casual partners. HIV-positive men, by contrast, were just as likely to have unprotected sex with regular and casual partners (22.2 vs. 20.6 per cent). The researchers argued that HIV-negative men cannot be sure of the HIV status of partners without mutual testing HIV-positive men, on the other hand, can find out their partners’ HIV status by the simple act of mutual disclosure. However it was not ascertained whether disclosure was what was driving up higher rates of casual unprotected sex in positive men.

We will look at evidence like this in the next section to understand how gay men are using disclosure to minimize HIV transmission risk. For the time being we are looking at the psychology of what condoms symbolize and why they tend not to get used in primary relationships.

An interesting insight into this was provided by a study from New York (Simoni 2000) which examined whether HIV-positive women had safer sex and if so, whether they did so more often in primary relationships. The authors hypothesized that women would be more likely to maintain condom use in steady relationships in order to protect partners.

They found the opposite to be the case. Forty-six per cent of women maintained condom use in all sex (in this study oral sex without a condom was counted as ‘unprotected’). But of the remainder, 61 per cent had had at least one episode of unprotected sex in the past 90 days compared with 16 per cent who had done it with a casual partner. Women in steady relationships were three times more likely to have unprotected sex with a steady than with a casual partner.

Was this because steady partners were more likely to be known to be HIV-positive themselves? No, because unprotected sex was just as common with HIV-negative male partners as HIV- positive ones.

On further investigation, condom use had a bipolar distribution. Condom use was significantly higher in women who had casual partners – but also within the most committed relationships, when these were defined by length (over one year), by being within a legalized marriage, or by partners living together. Condom use was a lot lower with primary partners who were new or whom the women did not live with.

The researchers theorized: “Women in our study who were married and in the longest, most supportive relationships may have possessed the power to broach or insist upon consistent condom use.”

Conversely, they add: “Perhaps in [more recently established] steady partnerships, condom use implies, not primarily protection, but mistrust, suspicion, lack of emotional and physical intimacy, or denial of potential motherhood.”

Ugandan President Yoweri Museveni used almost the same words when he address the Bangkok World AIDS Conference in 2004: “The best way to fight AIDS is with relationships based on love and trust, instead of institutionalised mistrust, which is what the condom is all about.”

Museveni’s words were attacked at the time by activists such as fellow-speaker Mabel van Oranje of the Open Society Foundation, who commented that his opinion “seems slightly drawn by ideology rather than an assessment of needs on the ground.”

But he may have been saying something more perceptive about human psychology as the reason why condoms can only ever form part, rather than the whole, of HIV prevention.