I could listen to Dr Qazi Rahman talk all day. Small, dark and engaging, Rahman has a unique ability to explain complex subjects in a way that not only makes them easy to understand but also interesting discussion points.
Last time I sat down for a glass of wine with Rahman, we talked in detail about the latest research on the sexuality of gay men (a subject close to my heart). We got such a strong response from Gay Star News readers to that article, that I wanted to hear more from Rahman and explore some other aspects of the fascinating world of human sexuality.
‘Let’s look at female sexuality,’ said Rahman taking a sip of the glass of Spanish white wine that had been recommended by our waiter. ‘There is a general assumption that female sexuality is generally more fluidic than that of males, and the current research really supports this.
‘An interesting starting point is that the number of women that identify exclusively as lesbian is about 1.5%, that’s about half that of the number of gay men.’
‘Another interesting fact is that of the self-identified straight women, anything up to 35% to 40% of women report they have had some sort of same-sex sexual experience or arousal.’
Rahman is quick to point out that research based on self-reporting or identification has its limitations.
‘Research that looks at physical responses provides us with a different level of insight because we’re looking at the involuntary physical response of a woman’s genitals. While female physiology is complex, by using a tool called a vaginal photoplethysmograph we’re able to record vaginal lubrication which is a strong indicator of sexual attraction and arousal.’
Apparently how this works is that participants in the study are shown footage of sexual activity. They get to see same-sex activity between men and same-sex activity between females. Footage of ‘straight’ sex isn’t used as it wouldn’t give a clear reading as it wouldn’t be clear whether the arousal was in response to the male or female.
Rahman explains that: ‘When these types of studies have been done with men, what we see is quite a binary response - self-identified straight men are only aroused by watching sexual activity between women; self-identified gay men are only aroused by watching sexual activity between men.
‘Women that identify as lesbians are only aroused by watching sexual activity between women.
‘However women that self-identify as straight or bisexual will generally show a more fluid arousal response in that they are aroused by footage of same-sex activity between men, same-sex activity between women; and footage of straight sexual activity.'
There is still continuing debate as to why this might be the case or what this may mean.
‘While we know that greater exposure of a female foetus to testosterone increases the chances of the child being a lesbian,’ says Rahman, ‘there is some suggestion that non-lesbian women don’t actually have a sexual orientation, that they’re not limited by physiological orientation.
‘That their self-identified sexual attraction category doesn’t necessarily match up with their physiological orientation doesn’t necessarily make their self-identification invalid, but it is an interesting insight into human sexuality - the primary purpose of which (according to evolutionary principles) is reproduction.’
In other words, women can think of themselves as straight and act straight but deep down inside they're all capable of being attracted to other women.
So if we’re saying, from a scientific perspective, that all females are in some way bisexual, what does this mean in terms of bisexuality in males?
‘When we look at self-identification studies, men will either identify as straight, gay or bisexual (meaning that they are equally attracted to the same and opposite sex). However the prevailing scientific view is that bisexuality in males doesn’t physiologically exist.
‘In physical response studies (using a recording tool called a penile plethysmograph), we find that self-identified straight men and self-identified gay men respond as you would expect with a category-specific response. So straight men are more aroused by watching footage of same-sex activity between women; gay men are more aroused by watching footage of same-sex activity between men.
'However 95% of of self-identified bisexual men are only aroused by the footage of same-sex activity between men, the remaining 5% are only aroused by the footage of same-sex activity between women.’
So you’re saying that there is no such things as a bisexual male?
‘The point is that male sexuality appears to be category specific. Bisexual males may exist but it’s likely that the numbers may be so low that it’s almost impossible to identify them through the available research.’
And we thought we had met lots of bisexual men!
What do we know about the sexuality of transgender people?
‘It’s very rare for someone to identify as trans. And the smaller the population available to study then the harder it is to identify the specific biological signals that have a material influence on the development of someone’s sexuality,' says Rahman.
‘Even though we don’t know a lot about the biology of trans people, we know enough to be confident that it’s not caused by social factors, that there is a biological explanation.
‘There are a couple of brain studies that suggest that trans people have differences in those parts of the brain that direct an individual’s sense of gender identity - tiny neural clusters or triggers that are somehow aligned to the female gender.
‘One slightly random fact is that we know that trans people are more likely to be left-handed.
‘The bottom line is that while social effects will play a part in the way that sexual attraction is expressed, sexual orientation is essentially innate. However the biology of sexual orientation is just the tip of our understanding of the sexual diversity iceberg.’
Rahman is assistant professor in cognitive biology and director of psychology programs at Queen Mary University of London. Obviously debate still rages in the scientific community about all the 'facts' on human sexuality and how they are analyzed. What is clear is that the research is evolving all the time. And it's fascinating. Meanwhile if you are a bisexual man or a straight woman, or anything else for that matter, don't let Dr Rahman or anyone else stop you.