Twins born from different fathers can occur in a biological process known as heteropaternal superfecundation. Photo / Getty Images
When twins Michelle and Lavinia Osbourne took at-home DNA tests to find out their real father, they discovered something extraordinary.
Not only were they not related to the man they believed was their father, they also had different fathers, a phenomenon that has only ever been recorded on 20 occasions, and never in Britain.
Twins with different fathers are ultra-rare. It is known as “heteropaternal superfecundation” and can occur when a woman releases multiple eggs during ovulation and has sex with two different men within her fertile window of around 12-24 hours.
The fertilised eggs both implant in the womb in their own placentas, like fraternal twins, but the babies born are half-siblings, not true twins.
The story has been revealed on the BBC Radio 4 podcast The Gift, which has been exploring the fallout from at-home DNA testing.
Michelle and Lavinia, 49, who now live in London, had a difficult upbringing. Their Jamaican mother came to Britain as part of the Windrush generation but ended up living in a series of foster and children’s homes, where she was sexually abused.
She fell pregnant with the girls when she was 19 and left them in the care of a family friend in Nottingham, telling them their father was a man called James.
The girls tracked James down when they were 15, but were never convinced he was their real father.
Michelle said: “I had deep down doubts about him. I saw a picture of James and I thought you don’t look anything like me, there is no similarity there. So I bought myself a kit.”
In 2021, Michelle decided to take an at-home DNA test and discovered that her real father was a man named Alex, whom their mother had met at a party in Leeds, and who was now living on the streets of London with a drug and alcohol problem.
Speaking of Alex, she added: “He’s dark, likely I get my long face from him, and I’m a combination of my mum and him. If you put the maths together, like two plus two, I’m the four.”
Although Michelle felt an instant connection to Alex’s family, Lavinia did not, and eventually took a DNA test herself, discovering that her father was a man named Arthur and that she was her twin’s half-sister.
“For about a month afterwards I just couldn’t stop crying,” Lavinia said. “I felt hurt, I felt shocked. I felt so many emotions.
“I just feel like something’s changed. [Michelle] was the one thing that belonged to me, the one thing that I was certain about, the one thing that I was sure of, and then she wasn’t.
“I’m not going to lie, it’s been a traumatic experience, and the only saving grace is I feel like I’ve found a place to belong and that place is with my dad.”
Michelle added: “I think she felt the tether had been cut, and tethers are quite often a negative thing, but her tethers were her sense of safety and family and all of a sudden she is not 100% my twin sister.”
The pair have had different experiences of meeting their real fathers. Lavinia now calls Arthur “Dad” and the pair meet regularly. However, he has glaucoma, so has never seen his daughter.
Michelle sees her father regularly too, begging in Brixton, south London, near where she works.
“Alex is a really nice man and has got a really soft spot in everyone’s heart, however he is not in a good place because he has been ravaged by drugs and alcohol and vagrancy and homelessness and begging, and he is not the man he used to be,” she said.
“He is one of the men that begs in the market looking for the money to pay for drugs, so I see my father all the time but he doesn’t recognise me.”
Professor Allan Pacey, from the University of Manchester, has spent more than 30 years researching reproductive health, but has never come across a case of twins with different fathers. But he says it may be more common than the statistics show.
“In order for this to happen the woman has to ovulate two eggs within the same cycle, quite a rare event in itself and she will have to have sexual intercourse with two men within the same 12- to 24-hour period around the time of ovulation,” he said.
“We know that there are only a very small number of cases recorded worldwide. But how do such cases come to light? Why would anyone suspect that twins might be from different fathers?
“Previous cases of heteropaternal superfecundation have only come to light in legal cases of disputed paternity, or when the two twins are born and are racially very different or when there has been a medical reason to test the genetics of both of them.
“I would imagine that in many happy families the paternity of twins may never be questioned, if they are of the same race and there are no medical problems to investigate.”
The full box set of The Gift is available now on BBC Sounds. The series starts on BBC Radio 4 on May 5 at 9am.
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