Nearly a third of bisexual men in the Natsal study were living with a woman.

Behaviourally bisexual men (BBM) had three times as many partners as men who reported having exclusively female partners (MEFP) and were less likely to undergo HIV testing.

The authors considered the potential of BBM to facilitate sexually transmitted infection (STI) and HIV by comparing sexual behaviours and attitudes with men reporting having exclusively male partners (MEMP) and MEFP.

The 2001 National Survey of Sexual Attitudes and Lifestyle (Natsal 2001) used a probability sample of the British general population aged 16-44 years between 1999 and 2001. A total of more than 5,000 men were surveyed.

BBM men accounted for 1.3% of all men who reported sex in the past 5 years and 44.1% of all men who reported having sex with men (the remainder being MEMP).

Nearly a third (29.0%) of BBM were married or cohabiting with a woman. The median number of partners in the past 5 years was 7 for BBM, 2 for MEFP and 10 for MEMP. STI diagnoses were similar in terms of proportions among the 3 groups, but BBM were less likely than MEFP to report HIV testing in the past 5 years.

The authors note that the findings have implications for health promotion as BBM are unlikely to be targeted specifically for prevention campaigns.

However, there is another important message for all those working in any setting that involves taking a sexual history: just because a man has a girlfriend or wife, we should not assume he has no male partners.

If we continue to make this sort of assumption, opportunities for STI, HIV testing and health promotion e.g. offering hepatitis B vaccination, will be lost.

Mercer CH, Hart GJ, Johnson AM. et al Behaviourally bisexual men as a bridge population for HIV and sexually transmitted infections? Evidence from a national probability survey. Int J STD & AIDS 2009; 20: 87-94