Women’s sexuality is vastly understudied in science and is still considered a “taboo” subject. Often, the experiences of men have been taken as the norm in scientific research, yet there are important differences in the sexuality of men and women.
In 2020, approximately 3.2% of the population in the UK over the age of 16 identified as lesbian, gay or bisexual. But when it came to bisexuality, there was a stark difference between men and women: women were much more likely to identify as bisexual compared to men (1.6% of women compared to 0.9% of men).
Similarly, a study conducted at the University of Notre Dame found that women were three times more likely to identify as bisexual. “Women have a greater probability than men of being attracted to both men and women,” said researcher Elizabeth McClintock, when discussing the results of the research. “This indicates that women’s sexuality may be more flexible and adaptive than men’s.”
The evidence overwhelmingly shows that women are far more likely to identify as bisexual than men. But it’s hard to say why this might be. Could it be that women are more innately bisexual? Or could it be the fact that it’s more culturally accepted for women to be sexually fluid, or to identify as a lesbian or bisexual than it is for men to identify as something other than straight.
Of course, it’s difficult to separate the cultural and biological but research into sex differences in genital arousal may be able to tell us more.
Women’s bisexual arousal
Genital sexual arousal or physiological arousal is the bodily response to sexual content. In men, it’s measured by changes in the circumference of the penis. In women, it’s measured using changes in blood flow in the vagina.
Research into genital sexual arousal has found that women are more likely to display a bisexual pattern in their sexual arousal compared with men, regardless of their sexual orientation. The 2016 study found that men are much more likely to experience sexual arousal towards one sex, whereas women are more likely to display genital sexual arousal in response to sexual videos of both men and women.
Our lab at the University of Essex has continuously found women are more likely to have bisexual physical responses than men. Research led by Gerulf Rieger, found that straight women showed a similar sexual arousal response towards both sexual videos of men and sexual videos of women. This is the case even though all women in the study said that they were only attracted to men.
Why is this the case?
The most prominent theory as to why women display a bisexual arousal pattern is what’s known as the preparation hypothesis. This hypothesis proposed in 2011 by researchers Kelly Suschinsky and Martin Lalumière suggests that because rape and sexual violence has occurred so much throughout human history, women have evolved to become physiologically aroused by sexual situations – even if they dislike or are disgusted by them.
This is believed to be because physiological arousal allows the vagina to become lubricated, thus reducing the likelihood of genital injury that could occur through sexual violence.
One study that seems to support this theory found that women displayed genital arousal while watching animal sex (bonobo chimpanzees). However, a 2018 study of 20 women found that watching sexually explicit films didn’t automatically lead to vaginal lubrication.
This study still needs to be replicated, as it’s complex to measure vaginal lubrication, but the results indicate that there may be flaws in the scientific thinking that women are turned on by anything sexual. Indeed, it’s likely many women reading this feel they don’t need a study to tell them they’re not aroused by any sexual situation.
Another theory we are currently investigating is whether empathy could be an explanation for women’s bisexual arousal. Studies show women are naturally more empathetic than men, especially towards other women.
Women are also more able to synchronise their own emotions with the emotions of somebody else. This means women may be more able to understand and feel what somebody else is feeling. And in terms of sexual feelings this could mean that if a woman were to watch a sexual video of a woman who is aroused, she may also become aroused due to her empathy.
While this new theory is still being studied, it’s clear that due to the complexity of cultural and biological factors involved, and because of limits to the current hypotheses we have to explain arousal patterns, conclusions can only go so far.
And while the research does suggest that women are much more likely to identify as bisexual and experience more bisexual arousal than men, more research is needed before we can truly understand why this is the case.