Five total strangers and the shocking scandal that would bond them for life 

To his surprise, Joey Hoofdman found out he was related to (clockwise from right) Marsha Elvers, Martijn van Halen, Peter Liefhebber – and many others

Joey Hoofdman still gets goosebumps when he describes the moment he saw a picture of his biological father for the first time. The resemblance was striking and undeniable. The slightly aquiline nose, the straight-set eyebrows and the curve of his jaw – even the fall of his tousled blond hair was so familiar it was like looking into a mirror.

It came as little surprise: Joey had spent his unhappy childhood convinced that he could not be related to his volatile parents, a torment that almost drove him to suicide. But finding his biological father was not, as he might have hoped, a joyful moment of discovery. In fact, the truth was far more troubling.

The man staring back at him from the screen on his phone was Jan Karbaat, a Dutch fertility doctor who had successfully helped Joey’s mother conceive. It meant he had inseminated her with his own sperm instead of her husband’s as they had agreed. And Joey’s mother had no idea.

It thrust Joey into the centre of one of Europe’s biggest medical scandals. The trusted doctor had, without his patients’ knowledge or consent, been using his own sperm to inseminate the women who came to him desperate for a child.

At the time of his death in 2017, he was thought to have had 22 recognised children from several marriages, and was suspected of secretly fathering 22 more with his patients – without their permission. Now, three years on, there are at least 61 known offspring conceived in this way, and it is feared he may have fathered hundreds more over a period of nearly 40 years.

After finding Karbaat’s photograph on the internet, Joey, 33, was left in no doubt that he was one of them. ‘When I tell this story I still get an electric shock through my body,’ he says today. ‘I’d been so sure my father was not my real father, and this picture meant I wasn’t losing my mind. I sent it to my friends and asked them who it was, and they all replied, “It’s you, Joey”.

‘But what it meant was more complicated. Something like this had never crossed my mind.’

For Joey, and the 60 other confirmed children, the extent of the scandal is only now becoming clear. It has consumed the Rotterdam suburb of Barendrecht, where Karbaat ran his private clinic from 1980 until it was shut down by the Dutch government in 2009 amid reports of record-keeping irregularities.

The quaint suburb, with a population of around 48,000, is surrounded by green fields, windmills and the meandering banks of the Oude Maas river. But Karbaat’s misconduct has left many residents questioning if they might be related, with concerned husbands and wives carrying out hasty DNA tests.

Fertility doctor Jan Karbaat secretly fathered at least 61 children with his patients – without their permission

Fertility doctor Jan Karbaat secretly fathered at least 61 children with his patients – without their permission

He also distributed vials of semen to clinics in the US, Belgium Germany and Denmark. Could they also have been his own?

At the centre of the scandal, of course, are children like Joey, the legacy Karbaat has left in his wake. The half-siblings communicate on WhatsApp, new members joining all the time. Some say Karbaat’s actions have overshadowed their entire lives; others that he has done them no harm.

Joey now has at least 60 half-siblings – ironic given that, as a child, a supportive family is exactly what he lacked. His earliest memory growing up in Rotterdam with an elder brother and younger sister is of his parents fighting. ‘I wished I was not from my family and imagined being someone else’s child,’ he said.

He left home at 15, and when his legal father died in 2012, the unanswered questions about his parentage were brought into sharper focus. He became depressed and sought help from a psychiatrist, who urged him to speak to his mother. It was early 2017 when he finally worked up the courage to do so. Shocked by his questions, his mother admitted visiting Karbaat’s clinic but insisted she had seen the vial with his father’s name on it before she was inseminated. ‘She was shocked and angry. She wouldn’t talk to me. She thought I was implying she had been unfaithful.’

Joey retreated to his car and Googled Karbaat’s name. There was a picture of the doctor in his younger years – and details of rumours that the doctor had used his own sperm. ‘It was horrible, shocking. I didn’t know what to think.’

Joey got in touch with a Facebook group run by a woman who suspected she was also one of Karbaat’s children. She put him in touch with a private investigator, who gave Joey a set of DNA tests. He persuaded his siblings, and his father’s two children from his first marriage, to take swabs.

The results were explosive. Joey was not related to his father’s eldest two children, which meant he could only have been conceived with an unknown donor’s sperm. Not only that: his elder brother had been fathered by a different donor. Only Joey’s sister was revealed to be fully related to their parents.

‘I went to visit Karbaat’s house, full of questions. I spoke to his wife who kept telling me to ask my mum, to come back later and the doctor would give me a tour of the clinic.

‘Karbaat was, at the time, desperately ill. She knew that and didn’t mention it. A week later he died.’

The only way to get answers was to track down others wanting them, too. Joey attended a court hearing in which a small group was trying to force Karbaat’s family to release DNA evidence that would allow them to carry out tests to confirm that the doctor was their father.

At the hearing he met Moniek Wassenaar. There was an easy familiarity between the two, which only deepened when they returned to her Amsterdam home. ‘I thought, “[The décor is] the same style I’d use in my own house.” We decided to see if we were related and did a test. Two days later the results were back – we were half-siblings. That was the first match. It was very emotional.’

Joey put his results on a genealogy site that matches DNA results with others around the world. Very quickly, it paired him with Inge Herlaar, 39, an HR professional and mother of two who had grown up in Barendrecht. Inge had been curious about her heritage since, aged 25, her father had confessed that she and her brother had been conceived using a sperm donor. ‘My father was caring and nice, the kind of father you wish everyone could have,’ Inge recalls. ‘There was no doubt that he was still my father. But I was curious. I liked the idea my biological father could be Jon Bon Jovi.’

A week after sending her DNA to the genealogy site in June 2017, Inge received a call from Joey. ‘He said, “I think I’m your half-brother.” I was really stunned. We met two weeks later with three others, who I found out were all my half-siblings.

‘We were searching for the same features, the same life events. One of them, Marsha, was just so similar to me – I’ve since found out we share so many genes that our mothers must be somehow connected, too.’

While Inge was shocked about her link to the notorious case, she insists that Karbaat ‘doesn’t really appeal to me’.

‘If you think Jon Bon Jovi could be your father and it turns out to be Karbaat, that’s a little disappointing,’ she jokes. ‘But I don’t feel a connection with him. I have a father already, who raised me and loved me.’

Still, she insisted her American husband Wim, 61, take a DNA test to prove they weren’t related. She will also insist her sons test their partners before they have children – just in case. ‘Before this happened I thought nurture was more important than nature, that we are all a product of the way we are raised. But meeting Marsha, and all of the others, makes me realise you’ll never change that blueprint. Many of the Karbaat children are doctors or health professionals. It’s strange.’

A court decision in early 2019 finally allowed Karbaat’s DNA to be released for testing, which means more siblings keep joining the group. ‘When I saw it written down, I broke,’ Joey admits. ‘It was very emotional, almost too much to process. Now I’m no longer angry but I am curious. I have the puzzle in my head but I can’t put the pieces together.’

Both Inge and Joey worry they may have inherited Karbaat’s personality traits. Inge explained: ‘In HR, we often have to make decisions to let people go, and I worry if I’ve made the right decision. So I always try to discuss it with colleagues. Karbaat didn’t do the right thing so I have to try.’

‘At first I was asking my friends to tell me if I was being manipulative,’ Joey recalls. ‘I wanted to know if I was doing things, tricking people, in a way I wasn’t aware of. To have a more human understanding of him as a person would be helpful.’

Most of Karbaat’s legal family – except one son who provided some DNA – have refused to help the group.

Joey said: ‘We heard from the Karbaat family’s lawyer that he has put in his will that if family members decide to cooperate with us they would not get any money from his estate. He is blocking it, taking his secrets to the grave.

‘It is cruel. He told a newspaper weeks before he died that there were no children, that we were seeing ghosts. He was still denying it until the end.’

The impact on their mothers has been no less stressful. Joey’s mother, who learned her three children have three different fathers, has struggled hard to come to terms with the news.

Inge says it has been ‘terrible’ for her mother. ‘It’s such an intimate thing to do to someone,’ she adds.

The extended family is still learning how to function. It is ‘a lot of work’ to keep in touch with them all and every new member needs support. Not all of them get along, Inge confides, ‘like any family, in a way. On the other hand, you’re well connected. If I have a problem, I have a lawyer. There are several doctors. If something pops up I can call a sister or a brother. It’s really funny – and very convenient.’

None of Karbaat’s children will ever be able to confront their biological father to ask why. ‘I only have the information from the media,’ explains Joey. ‘Maybe he did it because of the money, maybe he had a God complex. That’s what everyone says. But I think, at the start, he just wanted to help mothers to have children. Later, he evolved and it became about needing money or the status.’ The sad reality is that Joey and his half-siblings will never get the answers from him.

The next step is a class action in Holland’s civil courts where 53 people – including children of Karbaat, others conceived at his clinic and former patients – are claiming damages against Karbaat’s estate. They will return to court, hopefully for a final time, to hear the verdict within the next few weeks. Joey hopes to reclaim the money he has spent on DNA tests, and compensation for the damage done to his mother.

But not all have joined the action. Some, like Inge, are just happy to have found connections with their half-siblings.

‘I cannot help that he is my father, and his legitimate children also cannot help that he is their father,’ she shrugs.

Last month, Joey and Inge visited Karbaat’s grave in Rotterdam. ‘It was the closest I could get to him,’ Joey says.

‘To tell him everything and to forgive him. That was the most important thing so I could have peace of mind. I’m still not responsible for his wrongdoings and his actions but I need to forgive him to move on. I deserve that.’

The Immaculate Deception will be available weekly on Apple, Spotify and all podcast providers from 18 March