They've been together 7 years, have a child. And have just found out they're brother and sister.

By GRACE JENNINGS-EDQUIST

Leandro and Adriana have been together for seven years.

Although they’ve never formalised their relationship, they consider themselves married.

The Brazilian couple have a six-year-old daughter and a lot in common, having both grown up without their respective mothers.

But their happy relationship was rocked to the core this month when they discovered the unimaginable: The pair are brother and sister– and the ‘mothers’ that abandoned them as babies are in fact the same woman.

The shock finding emerged last month when Adriana, 39, went searching for her long-lost mother, Maria.

She approached a radio station in her town, Sao Paulo, to ask for help –– and was reunited with her mother live on air. But as the Daily Mail reports, at the end of the interview on Radio Globo‘s ‘The Time Is Now’ programme, Maria revealed she also had a 37-year-old long-lost son.

His name? Leandro.

As Adriana made sense of the news, she began to cry uncontrollably.

“I don’t believe that you’re telling me this. Leandro is my husband,” she sobbed.

“Now I’m scared to go home and find out that Leandro doesn’t want me any more. I love him so much.”

Despite the crushing revelation, the pair — who have not revealed their surnames — decided to stay together.

And as Adriana told Radio Globo yesterday, she believes God wanted her to be with Leandro and that ‘only death is going to separate’ them.

“We thought it was funny that both our mothers had the same name, but it is a common name so we just thought it was a coincidence,” she said.

“At first we were really knocked by it all. But we had a family meeting and told everyone that we are going to stay husband and wife, whatever anyone might think…. 

‘We have so many plans together, nothing’s going to break us up, nothing.’

What is ‘Genetic Sexual Attraction’?

Although Leandro and Adriana’s story may surprise you, there may actually be a scientific or sociological basis for sexual attraction between siblings who were separated at a young age.

As a 2011 University of Illinois study published in the Personality and Social Psychology Bulletin found, people appear to be drawn to others who resemble their kin or themselves — with those findings leading psychologist RC Fraley to speculate: “It is possible [that] as Freud suggested, incest taboos exist to counter this primitive tendency.”

The phrase Genetic Sexual Attraction (GSA), coined by adoption support group founder Barbara Gonyo, is sometimes used to describe the sudden feelings of attraction to a sibling or parent after a family reunion. The Guardian reports that, while  the frequency of cases GSA cases is difficult to quantify, some post-adoption agencies estimate that elements of GSA occur in a shocking 50% of reunions.

As Gonyo argues in her book I’m his Mother but he’s not my Son, sexual attraction between siblings may be a byproduct of “missed bonding” that would have normally taken place between family members had they not been separated.

GSA may also be explained by the “Westermarck” affect — named after sociologist Edward Westermarck —  which holds that people living in close domestic proximity during the early years of life are desensitised to sexual attraction later in life.

Relatives who don’t live together miss out on the the daily events that prevent such attraction from occurring– so that, in effect, the ‘Westermarck’ effect doesn’t have a chance to work in those situations, as Canadian GSA expert and counsellor Dianne Mathes told CBC News.

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