Sets of identical twins where one is straight and the other is gay are being studied to find out the way sexuality works. Sarah Nunn and Rosie Ablewhite, both 29, were interviewed in the Times, Sarah is straight, Rosie is a lesbian, but they are identical and they had the same upbringing. Scientists are using sets of twins like Sarah and Rosie to try to unravel the nature vs nurture argument as a background for sexuality. “Any boyfriend instantly felt more at home with Rosie,” recalled Sarah, speaking to the Times, “She liked football, talked about boy things, played video games. 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 finding out that it was impossible to get romantic with her, they came back to Sarah.The scientists at the University of Essex, Gerulf Rieger and Tuesday Watts, used photographs from childhood for the controversial test. They then asked strangers to see if they could tell whether the twins had discordant sexual orientations. Some have criticised the work, suggesting that it reinforces gender stereotypes. But it suggests that markers of sexual orientation manifest in early childhood. Another set of twins, Matilda and Lily, 30, were also involved in the study, and said they anticipate that the study could answer one of their biggest unanswered questions. My mum and dad were fascinated. How can it be that one egg split and in such a large factor of our life we were programmed so different?” says Matilda.