TWINS spend their lives being compared.

Two people who look virtually the same are a continuous source of fascination.

But how about what’s on the inside?

How we are brought up and the social experiences we go through have a bearing on the relationships we form in adult life.

So, how can it can be, that identical twins, who are raised in the same way, have different sexual orientations?

This question has troubled Essex University student Tuesday Watts, who is writing a PhD on the subject.

Although it forms such a huge part of who we are, we know so little about where sexuality comes from.

More than 80 sets of identical twins have now come forward to take part in the unique study, being led by Tuesday and the university’s sexuality scientist, Dr Gerulf Rieger.

Dr Rieger said: “Some research has already tried to understand how our sexual orientation is linked to childhood experiences.

“However, these past studies have heavily focused on negative experiences during childhood and neglected the possibility that people may have had positive interactions with parents, siblings or peers that have shaped their sexual attractions and identities.

“By comparing these twins, we will have the ability to explore how the social environment can have an impact on sexual orientation and wellbeing, above and beyond our genes.”

The study focuses on identical twins where one is heterosexual and the other is homosexual or bisexual, and the influences of upbringing on sexual orientation and current life satisfaction.

Because these twins are virtually genetically identical, any differences in their sexuality or wellbeing must be due to other influences than their genes – influences we do not yet understand.

Miss Watts, 24, and who is in the first year of her three-year studies, said she had been working with identical twins who came forward after she promoted her research in various gay literature.

They have come from all over the world.

The research has comprised of several parts, including a questionnaire about life satisfaction and childhood experiences and examination of twins’ photographs and videos to analyse how they express themselves from childhood to adulthood.

The final part invites participants to come into the university’s sexuality lab and their pupil dilation and/or genital arousal is measured in response to sexual stimuli.

Miss Watts, from Halstead, said: “It is early days but we are hoping to pinpoint the ways these twins differ. Using all these methods we are hoping to come to a better, considered understanding.

“All of our sexuality forms such a big part of our lives and determines who we end up with and howhappy we are in life. it is a huge life process which should be explored more.”

The findings are likely to be published in research papers.

HARVEY and Luke Gardner, 23, are one of the sets of identical twins who have taken part in the study.
It was Harvey, who is gay, who came across the appeal for twins to take part on the internet last
November.
He said: “I find the subject area very interesting and it has been a question ever since I came out aged 17 and started thinking about who I was.”
But Harvey said the twins had the same upbringing at home and the same childhood interests.
It was only social time spent apart that started to show differences in their teens.
The pair were spilt into different classes at secondary school as it said it would help their development and they formed different friendship groups.
Harvey said: “Through those years, Luke had quite a masculine- orientated life, had lots of guy friends and was very sporty.
“I had the polar opposite – a very close-knit group, all girls.”
During that time the boys both shared time together too, such as at their jobs at Greggs bakery.
Harvey, of West Sussex, said: “When we were apart we became different, which goes against what is being said at the moment – that homosexuality is predecided.”
He added: “I would hope the study would widen people’s opinions – not just straight people but gay people as well, and what being gay could be.”