These twins were born within minutes of each other - but have different dads

Twins Michelle and Lavinia Osbourne have always shared a special connection.

But when Lavinia clicked on an email with results of an at-home DNA test in September 2022, she was filled with a sense of dread.

"Maybe subconsciously I knew," she says.

Her test results revealed something astonishing: non-identical twins Lavinia and Michelle don't have the same father.

They were conceived naturally, grown together in the same womb, and born to the same mother within minutes of each other - but they are half-sisters.

Michelle and Lavinia, 49, exist because of an incredibly rare biological process called heteropaternal superfecundation. For it to happen, a woman must produce more than one egg during the same cycle, the eggs must be successfully fertilised by sperm from different men, and the resulting embryos must survive the pregnancy.

Only around 20 cases have ever been identified worldwide. After months of researching their story for the BBC Radio 4 series, The Gift, I've found that Lavinia and Michelle are the only set of twins with different fathers ever to be documented in the UK.

For Lavinia, the revelation was devastating. She and Michelle had shared a difficult childhood where they were passed around between homes and carers. The only stability the non-identical twins had was each other.

"She was the one thing that belonged to me, the one thing that I was certain about, the one thing that I was sure of," Lavinia says. "And then she wasn't."

But when Lavinia rang her twin to share the news, Michelle felt differently.

"I wasn't surprised," Michelle says. "I'm still in amazement that this can actually happen – it's super weird, super odd, super rare – but it makes sense."

Michelle and Lavinia's mother was a vulnerable 19-year-old when she gave birth to them in Nottingham in 1976.

"She had suffered abuse at the hands of [her] stepfather," Michelle says. "My mother was in and out of foster care and children's homes throughout her childhood."

Whenever the twin sisters asked who their dad was, their mum always said he was someone called James. "He wasn't in our life," Michelle continues.

Their mother was absent for much of their lives, too. When they were five years old, she got a place to study at university in London, and left her children behind in Nottingham with her best friend's mother, who the twins called "grandma".

"Grandma was strict – not very emotional, not very cuddly. The one constant I had was Michelle," Lavinia says.

As long as she had her twin, Michelle says, she felt safe.

"It was her and I against the world."

Aged 10, the girls joined their mother in London. But within a few years, Lavinia and Michelle were sent away again, to live in one of their mother's old foster homes. They couldn't understand why their mum wanted to maintain a distance from them.

"Physically and emotionally, she was always out of reach," says Lavinia.

After being absent for most of their childhood, James came back into their lives when the twins were in their mid-teens. Lavinia managed to track him down - and while she thought she recognised herself in him, Michelle never felt sure he was her dad. Deep down, there were niggling doubts.

By late 2021, their mother had early-onset dementia, and was no longer able to answer their questions. Michelle saw a photograph of James, and became more convinced than ever that he couldn't be her father.
 
"I just thought, you don't even look anything like me," Michelle says. "So I bought myself a kit."

If you take a DNA test, you reveal truths about your family as well as yourself. But Michelle wasn't thinking of how her results might affect Lavinia when she sent her sample off to be analysed. The results arrived on 14 February 2022 - the same day Michelle and Lavinia's mother died.

James's last name didn't feature in Michelle's paternal line - he wasn't her father.

After weeks of investigation, Michelle discovered that her father was Alex, the brother of a woman who had been friends with their mother. Michelle contacted some of Alex's family, who warned her he had struggled with alcoholism and drug addiction for years, and was living on the streets.

Michelle and Lavinia met up with a woman called Olivine, who Michelle believed was a new first cousin to both her and her twin. Michelle felt an instant connection.

"I just knew she was blood," she says. But Lavinia didn't feel the same. And when Olivine took out photographs of her family, Lavinia didn't see herself in their faces.

Lavinia decided to also do a DNA test. She didn't expect to get a different result to Michelle, but she had to do something about her growing feelings of unease that Alex's family was not her own.