On top of this, they both work as teachers and were both married on the same day... but the coincidences don't stop there.
Lin Backlund, 28, was more than a little sceptical when she received a Facebook message from a woman claiming to be her twin sister.
“I thought, ‘What crazy person is this',” she tells The Local, adding that she ignored the message.
However, her curiosity aroused, Backlund approached her adoptive mother about the possibility of there being any truth in the unusual message, and was shocked to learn of a strange set of events that had been almost forgotten.
“My Swedish parents' taxi driver was the key to everything,” Backlund explains.
When her parents were taking her to Sweden from the orphanage in Indonesia, when she was just 8 months old, the taxi driver asked the parents what had happened to Nur Kasanah (the name of her sister).
“He somehow knew that my [birth] parents had a girl named Nur Hidayah, which was me, and he was enquiring about my sister who had left the orphanage in Jakarta four weeks previously. Some think he was our birth father, but we don't know,” she says.
The driver wrote the Indonesian names of the two girls down for Backlund's parents, who two years later arranged a meeting with other the adopting family who were also living in Sweden.
However, at the meeting, discrepancies were found in the adoption papers, and it wasn't clear whether the girls were actually sisters or just born on the same day.
“No one thought we looked at all alike, even back then,” Backlund chuckles, adding that the connection was forgotten and that the families lost contact.
That was 26 years ago.
But upon learning about this forgotten family history last year, Backlund decided to respond to the Facebook message, saying she was interested in meeting the sender.
Backlund wanted to see for herself if this woman, calling herself Emilie Falk of Helsingborg, was really her twin.
The women organized a meeting at Backlund's parents' home in Höör, with the aim of getting to the bottom of their sisterly mystery and to see where things led from there.
According to Backlund, she and Falk clicked immediately.
“It felt like we were sisters already,” she recalls.
“It felt like we'd known each other for a long, long time – even though we hadn't. I have two other sisters, but the bond here was a lot different. Of course, the bond with my sisters is a lot stronger as we were brought up together, but it felt like I had known Emilie for a lifetime.”
The sisters' unlikely story was highlighted earlier in the week by the local Sydsvenskan newspaper, which marvelled over the fact that Backlund and Falk, who were born on March 18th, 1983, in Semarang, Indonesia, had been living so close to one another for decades in southern Sweden.
The pair met several times since their first encounter, and eventually agreed to undertake a DNA test to find out once and for all if they were indeed biological sisters.
And when the DNA tests came in, Backlund and Falk were elated to discover that they were indeed twin sisters.
“It wouldn't have mattered to me what the result was, but I was so happy to know for certain,” Backlund says.
As the sisters talked more about the astonishing coincidence of their Swedish reunion, they slowly began to find more similarities.
They both work as teachers, both speak the same dialect of Swedish (Skånska), and even have similar tastes in wedding planning.
“When we started comparing photos and papers, we found out that we both got married on exactly the same day. Emilie's wedding was exactly one year before mine – to the day!”
But the final surprise was still to come.
“We even had the same wedding song – ‘You and Me' by Lifehouse. Not many people seem to have heard of it; it's not that common I think," Backlund explains.
"We were amazed.”
In terms of the future, the sisters are keen to dig deeper into their past, and hope to eventually determine the identity of the taxi driver back in Indonesia who provided the initial clues leading to the sisters re-uniting in Sweden nearly three decades later.
“We want to find out if we have any family left in Indonesia, that's our next step,” says Backlund.
“But we don't really mind what we find now that we've found each other again.”