A LESBIAN twin and her straight sister have been studied by scientists who are searching for answers about human sexuality.
Researchers hoping to identify genetic and environmental factors associated with sexuality hit the jackpot when they discovered identical twins Sarah Nunn, who is attracted to men, and Rosie Albewhite, who is attracted to women.
The 29-year-old sisters were investigated by scientists as part of a study aiming to learn more about how sexuality develops in childhood.
The sisters were among 55 other sets of twins studied by researchers at the University of Essex.
Sarah recalled Rosie's tomboy tendencies as they were growing up, telling The Times her boyfriends "instantly felt more at home" with her sister.
"She liked football, talked about boy things, played video games," she said.
"They'd be like, 'Sarah, you're really boring. I'm going to go and play with Rosie.'"
"I'd get jealous that they liked her better."
But Sarah was quick to understand that her twin wasn't interested in boys romantically.
"When they tried to get romantic with Rosie she'd say, 'That's not me'. Then they came back," she explained.
The new research will build on previous scientific studies that searched for signs of how sexuality, such as gender-atypical mannerisms of behaviour, manifests before puberty.
Academics have struggled to produce concrete results in the past due to difficulties determining whether reported behaviour patterns were remembered accurately.
But the new research using dozens of twins and photographs from their childhoods could shed light on the subject.
University of Essex psychology academic Gerulf Rieger and his colleague Tuesday Watts asked Sarah, Rosie and other twins with "discordant sexual orientations" to send them childhood snaps so they could been shown to strangers who were unaware of the purpose of the experiment.
The strangers were then asked to try and spot the signs of the twins' behaviour, clothing and play diverged and pinpoint how and when it happened.
The study is somewhat controversial, as suggesting firm links exist between sexuality and gender could be seen as reinforcing stereotypes about male and female behaviour, which some say is harmful.
BARBIE AND SUPERMAN
But pictures provided by the twins make this issue difficult to avoid and show Sarah styling herself as female characters like Barbie, while Rosie suited up as Superman.
As the years passed, Rosie said she remembered wondering why she was less interested in boys than her sister.
"I questioned it for so long," she said. "Sarah was really boy crazy."
Rosie even rejected her own boyfriend's advances at one point, realising she did not want to kiss him.
But Sarah stepped in and said: "I'm the same ... I will kiss you".
Dr Rieger said the research into differences pre-puberty unlocked valuable insights about sexual identity.
He believes the most likely explanation for the divergence in behaviour is something that happens before birth.
"Paternal hormones are the number one candidate," he said.
"Our theory is that even though twins are identical what happens in the womb is quite different.
"They can have different nutrition, different levels of hormones."
This article first appeared in The Sun and is republished with permission