Separated at birth for secret experiment
Years before they knew each other existed, Ellen Carbone and Melanie Mertzel had one thing in common - they both longed to have a twin sister.
Ms Carbone was "just always fascinated" by them, inventing an imaginary sister as a child and always felt strangely jealous when she met twins.
Ms Mertzel too thought it was normal to long for a twin.
"As I got older, I would say it, 'doesn't everybody want to (have a) twin?' And my friends would be like, 'no,'" she told 60 Minutes.
But at the age of 23 they would discover they had more than just a longing for a sister in common - because they were in fact identical twins.
Ms Carbone and Ms Mertzel had been separated shortly after their birth and adopted by different families, never knowing of each other's existence until a chance encounter saw them meet as adults.
Speaking to 60 Minutes the sisters revealed how they discovered their separation had been far from accidental and the tragic reason they've never been able to have the relationship they'd hoped for.
CHANCE RESTAURANT ENCOUNTER REUNITES TWINS
In 1990 Ms Mertzel, then 23, was working in her parent's restaurant in Brooklyn when Ms Carbone's aunt came in for a meal and was stunned to see a mirror image of her niece.
"She saw me and couldn't understand why I didn't recognise her and when I went over to her table, she asked me if I was adopted and I said no," Ms Mertzel told journalist Liam Bartlett.
"I don't know, you know, I don't go around saying that information."
But the aunt was persistent and two weeks later she returned to Ms Mertzel's work, this time armed with a photo of Ms Carbone.
The twins spoke for the first time that night.
"When I went home from work that day, I called Ellen and when I heard her voice, I was like, 'Oh my god. You sound just like me' and then we started talking about everything," Ms Mertzel said.
The sisters hit it off instantly.
"It was like what I've always dreamt of and wanted as like a reality," Ms Carbone said. "I couldn't believe that it was happening."
'THERE IS NO REAL END PRODUCT HERE'
While elated to be back together there was a dark side to the sisters' reunion - their separation had been no accident.
Ms Carbone and Ms Mertzel were one of four sets of identical twins who, along with a set of identical triplets, were purposefully separated at birth by the Louise Wise Adoption Agency.
The agency gave the separated twins and triples to families on the condition that experts would be allowed to observe their development as part of a study.
But they were never made aware that their adopted children were actually separated from their siblings, and it was in fact the reason why they were being studied by famed New York Psychiatrist Dr Peter Neubauer.
Dr Neubauer died in 2008 and has ordered the records of his study of the twins to be kept secret.
It's believed his study was to discover whether nature or nurture was responsible for how people turned out as it was a subject he was fascinated by, twins expert Dr Nancy Segal told 60 Minutes.
"It really does seem that the twin's suffering and the suffering of their parents and their siblings and everyone who knows them, was really for nothing," she said.
"There is no real end product here, nothing that we can say that we've learned. We've only learned how not to do research."
THREE IDENTICAL STRANGERS
Dr Neubauer's most famous subjects were triplets Robert Shafran, Eddy Galland and David Kellman who discovered they were all related aged 18 in 1980.
Documented in the 2018 film Three Identical Strangers, the brothers became instant celebrities thanks to their extroverted personalities and good looks, even opening a restaurant called Triplets.
But they too struggled with the truth of how they came to be adopted, with Mr Galland taking his own life in 1995 after struggling with manic depression.
For Ms Carbone and Ms Mertzel, the triplet's story was even more bittersweet.
"I was jealous of them," Ms Carbone said, "because they, like, bonded so well."
"When we met, Ellen was living with her boyfriend in Jersey and I was dating my
boyfriend in Brooklyn," Ms Mertzel said.
"We couldn't bond like they did, we had our lives already. And it doesn't sound
like a big difference in age, but boys at 18 and girls at 23 is more of a big difference than just five years, you know what I mean?"
Despite their best efforts they have not been able to become as close as they hoped.
"She should've been the closest person to me in the world, and she wasn't," Ms Mertzel said.
The sisters, along with other the other twins included in the study, are now fighting to get access to Dr Neubauer's study on their lives.
Ms Carbone said they were treated "like animals" and were "used basically as human guinea
pigs for their research"
"And I was very, very shy as a child and I clung to my mother," Ms Mertzel said.
"I would hold onto her leg when we went out anywhere and I feel like that's because I was missing my other half, basically."
To watch the full 60 Minutes interview head to 9Now
Originally published as Separated at birth for secret experiment