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Institute for Global Health blog



Heterosexual-identifying men who have sex with men: an understudied population

By Rebecca C Parrish, on 17 May 2019

Written by Tyrone CurtisPhD candidate, Institute for Global Health


Since the start of the HIV/AIDS epidemic in the 1980s, much public health focus has been on the sexual health and sexual behaviour of men who have sex with men, or MSM, and in particular, men who identify as gay or bisexual. However, we know much less about MSM who identify as straight or heterosexual. These men, who I refer to as heterosexual-identifying men who have sex with men, or HI-MSM, are the focus of my research.

Who are heterosexual-identifying MSM?

Most people, when they think of this group, tend to think of men who have some same-sex attraction but are “in the closet”; that is, men who are “actually gay or bi” but just haven’t been able to admit it yet. This could be because they’re from a culture that stigmatises gay or bisexual identity, or because these identities conflict with other identities these men hold. However, some HI-MSM have little to no same-sex attraction (or not enough, in their view, to warrant calling themselves bisexual), but still enjoy sex with other men. The sex they have with men may be experimental, or something they do together with female partners (e.g. swingers). Sex with men may provide some HI-MSM with a sexual release they no longer get with their female partners, without the threat of emotional connection that would end that relationship. Others may just be much more relaxed about their sexuality (e.g. heteroflexibles or mostly straights), such that same-sex behaviour isn’t a threat to their heterosexual identity. In any case, their same-sex behaviour is not important enough to them to define their identity.

Data from NATSAL-3, a nationally representative survey of British adults aged 16-74 conducted in 2010-2012, suggest that around 22% of men with same-sex partners in the previous year identified as heterosexual, a little more than those identifying as bisexual (19%).

How do we study heterosexual-identifying MSM?

There is an obvious challenge in studying this population, and that is: where do we find them? Most studies of MSM recruit in-person at gay venues such as bars, clubs and saunas, or online via gay websites or social/sexual networking websites and apps. However, discretion is often important to HI-MSM, and so they are less likely to visit these places. As such, most samples of MSM recruit very few HI-MSM (typically around 1-2%), which makes analysis very difficult. This is a significant factor in our current poor understanding of this population.

Why are we interested in heterosexual-identifying MSM?

There is good reason to think that HI-MSM may be at risk of poor sexual health. HI-MSM are less likely to disclose the sex they have with men to healthcare providers, meaning they’re less likely to be given relevant sexual health information, offered regular testing for STIs and HIV, or offered preventative measures such as HIV pre-exposure prophylaxis (PrEP) or vaccinations for Hepatitis A & B. In addition, HI-MSM tend to be less involved with the LGBT community, either passively (because they have no connection to it) or through actively avoiding it. This means they are less exposed to sexual health campaigns which are promoted in the community, are less exposed to the norms of that community (e.g. frequent HIV testing, condom use), and may feel less comfortable accessing resources such as sexual health services within that community, especially if these are targeted towards gay men. As such, they may be poorly informed about the risks of their sexual behaviour.

In addition, these men are less likely to disclose their sex with men to female partners, potentially leaving those partners less informed when it comes to their own sexual decision making, particularly around condom use and other HIV/STI preventative measures. In this way, HI-MSM may also act as a bridge between the gay and heterosexual communities for HIV and other STIs.

What is my project about?

The aims of my project are to describe and characterise the sexual behaviour and sexual health of HI-MSM in Western Europe, North America, Australia and New Zealand; to compare their sexual behaviour and health to those of gay- and bisexual-identifying MSM; and to understand how HI-MSM perceive their risk during sexual encounters with both men and women, their experiences of and attitudes towards sexual healthcare, including HIV/STI testing guidelines; and also their feelings about HIV prevention measure like PrEP.

In recognition of the challenges of recruiting large samples of this population, I’m conducting my research using methods that avoid the need to recruit a large sample of HI-MSM. One component of my project involves carrying out individual participant data meta-analysis of behavioural surveys of MSM from Western Europe, Canada, Australia and New Zealand. Essentially, this involves pooling data from these surveys, each of which may only have a relatively small number of HI-MSM, in order to build a large enough sample of HI-MSM on which to carry out analysis. Special analysis techniques are used that take into account clustering within survey samples and countries (i.e. men within one country are more likely to act like other men within that country).

I will also be carrying out 15-20 semi-structured qualitative interviews with HI-MSM within the UK. This will allow me to ask more relevant questions than were asked in the various surveys included in the meta-analysis (which were written for MSM more general), and also allow me to probe more deeply into HI-MSM’s experiences, attitudes and feelings about the sex they have (with men and women) and with regards to sexual health and sexual healthcare.

By understanding more about the way HI-MSM engage in sex with their partners, and about their experiences with and feelings regarding sexual healthcare provision, we can better understand their sexual healthcare needs, and identify any gaps between these needs and current service provision. This will hopefully lead to more effective engagement with HI­-MSM, resulting in better sexual health for both them and their partners.

 keywords: sexual health, sexual behaviour, sexual orientation, hidden populations, men who have sex with men


Tyrone Curtis is a second year PhD student with an interest in the sexual behaviour and sexual health of MSM. Originally from Australia, he studied mathematics at the University of Queensland before moving to London in 2008. He completed an MSc in Applied Statistics with Medical Applications at Birkbeck College in 2014. When not at his desk, he can often be found in one of London’s parks hanging from a flying trapeze.

Follow Tyrone on Twitter: @spacepup84