‘Nobody is 100 per cent straight’
YOU may think you're only attracted to the opposite sex, but strictly straight people don't exist, according to a psychologist.
It turns out we're all bisexual, getting turned on by both men and women, regardless of what we say.
Researchers from Cornell University asked volunteers to watch a series of porn videos to test what turned them on and what didn't.
Their research questions society's strict definitions of sexuality and warns that we still struggle with the idea of bisexuality, especially when it comes to men.
Lead author Rich Savin-Williams suggests that sexuality exists on a spectrum and that younger generations are more open to the idea of fluid sexuality than older adults.
Both male and female volunteers were asked to watch porn involving men or women as part of the research.
Experts measured how much their pupils dilated - a sign of sexual arousal.
Women's eyes dilated watching both men with women and women with women.
And men's pupils dilated watching both men and women masturbate, regardless of how they identified sexually.
Dr Savin-Williams warned that cultural expectations of sexuality need to change in order for people to be more comfortable with who they are attracted to.
"We've always recognised mostly straight women, that is, women who mostly are straight but if the right woman comes along, well maybe she'll try it out. We used to think that was only a female phenomenon," Dr Savin-Williams told Broadly.
"There are aspects [of male sexuality] along a continuum, just as we have always recognised with women.
"Men have gotten so much cultural c**p put on them that even if a man does have some sexual attraction to guys, they would never say it."
Previous research has suggested that women's sexuality can change throughout their life.
Psychologist Dr Lisa Diamond of the University of Utah said it was not always the case that "once a lesbian, always a lesbian".
She added: "Historically, sexual orientation models assumed only two categories, exclusively homosexual and exclusively heterosexual.
"Anything else is 'transitional', 'confusion', 'experimental'. As a result, researchers routinely eliminated bisexual individuals from research samples. Big mistake."
Surveys show more people identify themselves as "mostly-but-not completely heterosexual" than exclusively heterosexual. The smallest group is those that are exclusively attracted to the same sex.
But other research has found that being gay is written in your DNA.
US researchers from NorthShore University in Illinois found sections of genes that may influence whether a man is gay or straight.
They scanned the DNA of 1,100 gay and 1,200 straight men and found two distinct areas of genes they believe play a part in male sexual orientation.
Rich Savin-Williams has written a book, Mostly Straight: Sexual Fluidity Among Men that follows on from the research.