Double take: the twins they never knew they had

Imagine finding out late in life that there's someone out there who looks just like you: same eyes, same nose, same mouth. Not a doppelganger, but a twin you never knew existed. Discovering that you're a twin is "a life-changing experience," says Nancy L Segal, a professor of psychology and the director of the Twin Studies Centre at California State University, Fullerton.

Segal has written nine books on twins and is now working on her 10th. Over the years, she has come across at least 100 pairs of reared-apart twins. In most cases the twins were separated at birth and adopted by different families. "Adoptees often feel that something's missing in their lives," Segal says. "I think it relates to the fact they don't look like their family members. They don't feel a certain kind of belonging, even though they're loved. When they find a twin, they can see themselves in somebody else. And that's important."

Through her research, Segal has found that twins are often similar even if they've grown up apart. "In personality, identical twins raised apart are as similar as identical twins raised together." This suggests we're similar to the people we live with because of the genes we share, rather than the environment. Segal has also found that identical reared-apart twins often feel closer than fraternal (non-identical) reared-apart twins. "What I've found even more striking is that when I've compared the twins' current closeness – both identical and fraternal – to the adopted siblings they were raised with, they felt much closer with the twin. I've been surprised at how well they got along so quickly. It seemed as if they'd known each other all their lives."

Here, people who've found their twin later in life share what it's like to discover this missing part of themselves.

'What freaks everybody out is our gestures': Tim Carpenter and Bill Henry, 62 When Tim Carpenter was 15, a security guard began following him at his local department store. "I started walking faster, trying to lose the guy," says Tim. "Finally, I asked why he was following me. He was mad that I hadn't said hello. I told him I don't normally say hello to people I don't know. The man said: 'What do you mean you don't know me? I go out with your sister!'" Tim was confused – he didn't have a sister.

Equally confused, the security guard went to get his girlfriend, Debbie, who told Tim he looked just like her brother. When Tim showed her his ID, she said, "You have the same date of birth as my brother!" They discovered that both Tim and Debbie's brother, Bill Henry, were adopted and lived seven miles apart in Rhode Island. This was August 1977. Debbie suggested that Tim and Bill meet at a football game between their two schools that October.

That night, Debbie told her family she had met Bill's twin. Their mum didn't believe it, but Bill was intrigued. He played sports at high school and, when they played with one particular other school, people mistook him for someone else. "I said: 'It's got to be the same kid,'" says Bill. "My sister says he looks like me and his date of birth is the same."

By the time the football game in October came around, Tim had forgotten about Bill. But Bill was there and he noticed three girls staring at him. "I said to my buddy, 'Those three girls think I'm this kid, Timmy Carpenter. Just watch'," says Bill. He told them that he wasn't Tim, but that he had come to the game to meet him. His house was close to the stadium, so two girls went to get Tim, while the other stayed with Bill.

"The first thing Timmy and I said to each other was: 'I don't look like you,'" says Bill. "Timmy weighed 30lb more than I did, was a little taller and had a moustache. But everybody in the stands freaked out when they saw the two of us."

Next, they arranged to meet their adoptive parents to compare paperwork. They continued to discover similarities and shared interests – from their mannerisms to having the same favourite baseball player. "The thing that freaks everybody out is our gestures – how we talk with our hands, how we move," says Bill.

Five years later, when they were 21, they got their adoption records from the state, which confirmed they were twins and had three other siblings. "It was interesting to know that there were other siblings, but I didn't look for them," says Tim. Bill felt the same. Their families continued to meet and they'd often see each other over Christmas. When Bill went to college, Tim would go and visit him and they'd swap places and prank his friends.

Do they ever wish that they'd grown up together? "I've thought about it," says Tim. "It would have been..." Bill chimes in, "a lot different". They're both grateful for their adoptive families, but glad to have found each other. Now, living on opposite sides of the state in Florida, they keep in touch over the phone. "Going through school with Tim and doing things together would have been nice," says Bill. "But I don't think it would have changed our path."

'Our bond is so much more than looking alike': Debbie Mehlman and Sharon Poset, 72 In 1997, when Debbie Mehlman was 45 years old, her mum said they needed to talk. Debbie thought this was "the money talk" – that her mum was getting her affairs in order and sharing her account details. Instead, she turned Debbie's world upside down. "She tells me that I'm adopted and there were two babies. I was like: 'What!'" says Debbie. "Once I got over the shock that I'd been lied to my whole life, I thought: 'I have a twin, I want to meet her.'"

Debbie hired a private investigator to track down her twin, who turned out to be a woman named Sharon Poset. The investigator found Sharon's adoptive parents first. Unlike Debbie, Sharon knew she was adopted from a young age, but she had no idea she was a twin. Her parents didn't know either – they went to see her in person to break the news. When they sat her down, Sharon had the same thought as Debbie. She, too, thought they were about to talk about money.

Debbie was raised Jewish; Sharon was raised Catholic. They grew up in New Jersey, about 40 miles apart. They both had non-biological sisters who they weren't close to, so when they discovered they were twins, neither thought they would have a strong bond.

After talking on the phone for a week, Sharon went to stay with Debbie in Connecticut for a weekend. "We didn't reach the falling-in-love stage straight away," says Sharon. "But five minutes later..." Debbie interjects. "We started talking and we're both doing this [she gesticulates] and rolling our eyes. We're like, 'Oh, she does the same things I do.'" They had different hairstyles, but similar features. "I asked Debbie: 'Did you have a unibrow in high school?' We both started laughing. That's all we did the whole weekend."

Later, they went out for lunch with Mehlman's friends. "Without the other knowing, we kept looking at each other to make sure we still looked the same," Mehlman says. Later they confessed they'd done this. "It blew us away," says Poset. "We thought: who cares if our hair isn't the same? Our brains are thinking..." Mehlman joins in: "The same!" They often speak in unison or finish each other's sentences.

The private investigator also tracked down the twins' birth mother, a German woman who'd married an American soldier, moved to America and had a child with him. On a trip to Germany without her husband, she slept with a staff member on the ship, got pregnant with the twins and subsequently gave them up for adoption. Sharon's mum had just had a miscarriage and Debbie's mum couldn't conceive, so they were each given one of the twins. Sharon met their birth mother once, but their mother wasn't interested in having a relationship with them.

Now, 27 years after they reunited, Debbie and Sharon feel closer than ever, despite living 1,000 miles apart. Sharon now lives in Alabama; Debbie lives in Connecticut. They meet when they can, speak on the phone once a week and text often. They aren't resentful that they didn't grow up together. In fact, they think they would have tried to assert their individuality if they had. Instead, they celebrate their similarities. "The first thing people ask when they hear our story is: 'Do you look alike?'" says Sharon. "But the bond is so beyond that."

'It was as if we'd always known each other': Jerry Levey, 70, and Mark Newman Jerry Levey was raised in New York by adoptive parents. He knew he was adopted from the age of 13, but he had no interest in his biological family. When he was in his late 20s and working as a firefighter, he moved to New Jersey, which inadvertently set him on a path of discovery about his past.

In 1985, aged 30, Jerry went to the New Jersey state firefighters' convention. "I noticed people staring at me," he says, Eventually, a stranger asked if he had a twin brother. "I said: 'Not that I know of. I'm adopted.'" The stranger told Jerry there was a firefighter in their fire company who looked exactly like him. "I thought they'd been partying too much."

The stranger asked when Jerry was born, and Jerry told him: 15 April 1954. They swapped numbers and the stranger said he would check if the man he knew had the same birthday. The next week, Jerry received a call to say the man, Mark Newman, was also born on 15 April 1954. Jerry suggested they brought Mark to see him. "They got him there under the pretence of looking at a piece of apparatus. His friends walked into my firehouse and my jaw dropped. Here comes his bald head, just like mine, walking into my firehouse."

Mark also noticed the similarities immediately: the way they walked, their facial expressions. "We dressed alike: blue jeans and T-shirts. We had the same glasses and moustache. He had a keyring hanging from the right side of his belt, so did I. He had a rescue knife on the left side of his belt, so did I," says Jerry. "We had the same voice. When he spoke, I thought I was talking to myself. Looking at him, I kept thinking: 'Am I looking in a mirror?'"

Jerry says it was "one big party" from then on. They hung out at weekends and stayed in touch for the next 25 years. But in 2011, Mark moved to Arizona and they lost contact. Jerry says his brother went into "hibernation" and cut himself off. He never knew why. Eventually, in 2022, Jerry heard that his brother had died.

"I always thought there was something missing [in my life]," Jerry recalls. "But I didn't know what it was. When I found out I had a twin, I thought: 'That's why I felt that way.'" He still thinks of Mark and remembers their time together fondly. "We were reared apart but we acted like twins. It was like we'd always known each other."

Lin Ahle was two months old when she was adopted by a Swedish couple. They picked her up from Indonesia, where she was born. On the way to the airport to return to Sweden, something strange happened. The taxi driver asked her adoptive parents: "What about the other sister?" He then wrote down Lin's Indonesian name and another girl's Indonesian name. "We still have that note," she says.

Back in Sweden, Lin's adoptive parents tried to find out if there was another baby born at the same time. They were part of a group of parents who had adopted children from Indonesia – they thought one of them might be this "other sister". "They compared the adoption papers and found similarities but also differences," says Lin. "You couldn't tell from the papers if we were sisters." Having waited a long time for a baby, both sets of parents decided not to rock the boat. "They thought: if the girls ask, we'll look into it again. But we never did," says Lin.

That all changed in 2010, when Lin received a Facebook message from someone called Emelie Falk. The message said: "Hello, I think you might be my sister." "I think Lin thought I was crazy," says Emelie, who is also Indonesian and grew up in Sweden. Emelie had never been interested in her biological family, but she got curious after thinking about having kids herself. "My mum said: 'I told you that you might have a sister.' I said: 'You never told me about that!'" Emelie says.

Through a parent from the adoption group, Emelie found Lin's parents' names. After some Googling, she found Lin's Facebook profile. Feeling sceptical, Lin called her parents. Like Emelie's parents, they said they'd told her she might have a sister. "They showed me a picture of us when we were three at this Indonesian adoption group. They said: 'Don't you remember?' I said: 'No, I was three!'

After the Facebook message, the pair spoke on the phone. They discovered they'd both studied to become teachers, they loved interior decorating and they got married on the same day, but one year apart. They even had the same first dance song, You and Me by American rock band Lifehouse. "It's a very uncommon wedding song. So that was crazy," says Emelie.

Two weeks later, they met at Lin's house. "We were nervous – it felt like a first date," says Emelie. "But at the same time, it felt special. This was someone I'd missed all my life – I just didn't know it." Lin felt the same. They aren't identical twins, but they have physical similarities. "The first thing I noticed was she had long front teeth like me," says Emelie. They'd grown up about 20 minutes' drive from each other, and still lived only 30 minutes apart. They wondered if they'd ever unknowingly crossed paths. After comparing their adoption papers, they got a DNA test, which confirmed they were twins. "I was crying and screaming," says Emelie.

Since finding each other, Emelie and Lin have taken part in a documentary in which they met their birth parents and other siblings – they have 15 in total, including twin brothers. Both sets of twins were put up for adoption because their parents couldn't afford to keep them. In Indonesia, it was also considered bad luck to have twins. As for the mysterious taxi driver? They still have no idea who he was.

These days, Lin and Emelie speak often and meet when possible. They're grateful for their relationship. "Even though we didn't know we were missing something, we now feel complete," says Lin. "We always have each other's back," says Emelie. "Lin is one of the most important people in my life."

'We felt the greatest sense of empathy': Sam Futerman and Anaïs Bordier, 36 Anaïs Bordier was 25, living in London and studying fashion, when her friend tagged her in a Facebook post that stopped her in her tracks. It was a screenshot of a video and the person who appeared in it looked eerily similar to her. Watching the video, Anaïs couldn't believe how alike they looked, but she couldn't find any information about who the woman was.

Born in Busan, Korea, Anaïs was adopted at three months old and raised in Paris. She always knew she was adopted and, as she had her adoption papers, she thought she knew everything. But the Facebook post made her think. Who was this woman?

Two months later, the friend who'd posted the screenshot came across a film trailer featuring the same woman. Anaïs found the cast list and saw that someone called Sam Futerman played "Asian girl". "I looked up her profile and discovered she was born on 19 November 1987, which is my birthday," says Anaïs. "I thought I was seeing things."

Her brain went into overdrive. She called her parents and decided to send Sam a Facebook message. But because they weren't Facebook friends, Sam didn't see it. Finally, on the day of Sam's film premiere, she was scrolling through Facebook when she saw Anaïs's friend request. "I clicked on it and thought: That's weird, she looks like me," says Sam. She accepted the request.

Anaïs sent a message. "It said: 'Hi, my name is Anaïs. I'm French. I live in London. I was born on 19 November 1987, too. Are you adopted?'" recalls Sam.

After a few days of messaging, they spoke over Skype – for three hours. It was strange to meet someone with the same face, but a completely different accent (Sam grew up in New Jersey.) They realised they had the same laugh, a shared love of Harry Potter and an aversion to cooked carrots. "We talked about everything," says Sam. "It was weird, because you're basically meeting a stranger but you feel connected," says Anaïs.

Three months later, they met in London and spent 10 days together, along with friends and family. Their first meeting was at an Airbnb in Shoreditch. Sam heard Anaïs laughing in the hallway and she suddenly couldn't stop laughing. "It was nervous, crazy laughter," says Sam. "Anaïs kept getting closer and I kept moving away."

Eventually, they stood back to back and compared their hands. "Anaïs poked me in the head," says Sam. "I had to make contact. She was hysterically laughing!" says Anaïs.

Walking around London, they would catch their reflection in a shopfront and couldn't work out who was who. "Being an adoptee, I'd never found anyone that looked like me. All of a sudden, having someone that looked exactly like me was weird. But we felt the greatest sense of empathy that you could feel with another person," says Sam.

Before meeting, they'd done DNA tests. They got the results while they were together, which showed that they were identical twins. "It was the icing on the cake – that final confirmation," says Sam.

Since their reunion more than 10 years ago, Sam and Anaïs have grown closer. While Anaïs lives in Paris and Sam lives in California, they text constantly and meet at least twice a year, taking it in turns to visit each other.

The twins haven't been able to track down their birth parents, but they are open to reconnecting. "What happened in the past is the past, and we still care for them," says Sam. "It's unfortunate we were separated, but so many amazing things have happened since that we wouldn't change it. We're just happy to be together now."

For Anaïs, the experience has made her more positive. "Going from having no one who looks similar to you to having someone who's identical to you is overwhelming – it filled a void inside me. I feel so fortunate."