Newspapers and websites have been taking great delight this week in declaring that “no one is 100 percent straight”. Apart from the fact that if no one is 100 percent straight, then it should follow that no one is 100 percent gay, either, the idea that sexuality is fluid is hardly a new one.
The stories have been fueled by psychologist Ritch C Savin-Williams, who specializes in gender studies. He maintains the view that sexuality is a spectrum, most famously introduced by Alfred Kinsey, but adds that because of society and the cultures we grow up in, there is a stigma around admitting that you are anything other than “gay” or “straight”, particularly when it comes to men.
The main assertion seized upon by outlets about no one being straight, though, is based on a 2-year-old study looking only at women who self-identify as “straight”, “mostly straight”, “bisexual leaning straight”, “bisexual”, “bisexual leaning lesbian”, “mostly lesbian”, or “lesbian”. They were then shown either all male, all female, or mixed porn, and their physiological responses measured to get an idea as to whether or not they were aroused.
This included tracking the dilation of their pupils, as well as the slightly more intimate changes in the pulse and blood flow of their genitals while they were watching the films.
The study showed that those who identified as lesbian were unsurprisingly significantly more aroused by their own sex than the opposite, but they also found that those identifying as straight were on average aroused by both male and female sexual stimuli. This much is true.
The important part of that sentence, however, is the “on average” bit. This means that while some of the women who self-identified as straight did get aroused by female porn, and so might not be "100 percent straight", some of the women didn't, and so were right in identifying themselves as heterosexual. The table above, taken from the study, shows this in regards to the women's genital changes, while the one below shows self-identification accuracy based on pupil dilation.