New research indicates that HIV-positive gay men in north-east London are more likely than HIV-positive black African heterosexual men and women to engage in risky sexual behaviour. The behavioural research focused on people living with HIV receiving treatment and care in outpatient clinics in north-east London. During 2004-2005, patients were asked to complete a confidential, self-administered questionnaire so researchers could examine the sexual behaviour of groups living with HIV. Respondents were asked about unprotected anal or vaginal intercourse in the previous three months, the type of sexual partners they had (main or casual) and the HIV status of their partner or partners. Of the gay male respondents living with HIV, nearly 40% reported unprotected sex in the previous three months; 14% only with HIV concordant partners. One in five gay men living with HIV reported unprotected anal intercourse with an untested partner or a partner of a discordant HIV status, presenting a risk of HIV transmission. By comparison, one in 20 black African heterosexual men and women with HIV reported unprotected vaginal intercourse that presented a risk of HIV transmission. HIV concordant unprotected sex was reported by 6.6% of respondents in this group. Most HIV-positive black African heterosexual men and women reported unprotected intercourse with a main partner rather than with a casual partner. In contrast to this, the gay male group reported higher rates of unprotected intercourse with casual partners than with a main partner. The largest difference was seen when reporting unprotected sex with casual partners of unknown status; 15% for gay men and 1% for black African heterosexual men and women. The results highlight the fact that gay men are likely to continue to account for the majority of new HIV infections acquired in the UK for the foreseeable future and emphasise the continued risk of HIV transmission during casual sex encounters. All eligible clinic attendees were asked to participate and 73% (over 1,600) completed the questionnaire. This included 480 black African heterosexual women, 224 black African heterosexual men and 758 gay/bisexual men (464 white, 112 other ethnicity). Unsafe sex between two HIV-positive partners was also discussed. While serosorting poses no risk of HIV transmission to an uninfected person, the researchers pointed out that unprotected sex between two HIV-positive individuals carries a risk of HIV cross-infection and transmission of other infections. Ref: AIDSMAP (m)