After 3 decades twins discover their dad is not their father

The matter first came to light when Wout had a blood test at the doctor's for a check-up. The results showed that he has blood type B. ‘I immediately called my doctor to ask if they were absolutely sure. My father has blood type A and my mother has blood type O, so it was impossible for me to have B.’

‘It was only later that it dawned on me that we were conceived through IVF, so something could have gone wrong there,’ says Wout, who is immediately faced with a lot of questions. ‘Are both my mum and dad not biologically related to me? How did something go wrong? Was I the only one who was switched?’

DNA test provides certainty

The family decided to have a DNA test done. It confirmed that during the fertility treatment at UZ Brussels, a sperm sample from another man had been used. Bart turned out not to be the biological father of Siska and Wout. No children are believed to have been born into another family with his sperm sample. Mum Kristin is biologically related to the twins.

‘Born out of a mistake’

‘The first thought that went through my head was: I've lost two children,’ says father Bart from Mortsel (Antwerp Province). His family's world has been turned upside down since October last year. After 30 years, it suddenly turns out that he is not the biological father of his children Wout and Siska, twins he had with his ex-wife in 1995.

‘The news came as a complete shock. It's such a jumble of emotions, thoughts and questions that go through your mind,’ says Siska, Wout's twin sister. ‘Questions about my right to exist, among other things. You were born out of a mistake and, in fact, no one really asked for you to be here in this combination.’

‘For me, that's one of those feelings you can't explain,’ adds Wout. ‘Feelings you can only understand if you experience them yourself.’

‘I wanted to give the others space to process it in their own way,’ he continues. In addition to Siska and Wout, there is also a second set of twins in the family. ‘They are suddenly my half-brother and half-sister,’ says Siska.

UZ Brussels responds: ‘We are cooperating fully’

In a response, UZ Brussels acknowledges that the wrong sperm sample was used. ‘We suspect that this happened in the lab's workflow on the day of this family's procedure’ the hospital says.

UZ Brussels has a strong suspicion who Siska and Wout's biological father is, but is not releasing his identity for the time being. ‘We have to take into account the legal context, medical confidentiality and privacy,’ the hospital says.  Siska and Wout have now taken UZ Brussels to court. They want to compel the hospital to disclose the identity of their presumed father.