Jan Karbaat died in 2017. Then 49 people came forward to claim they were his children.

It reads like a Hollywood movie script.

Jan Karbaat was a well-known IVF doctor in the Rotterdam suburb of Barendrecht. For many years, the Dutch doctor helped countless women become impregnated in the clinic behind his home.

Then in 2009, the clinic was closed down due to irregularities. According to the Telegraph, authorities alleged Karbaat had falsified data and donor descriptions, and exceeded the permitted limit of six children per a donor.

But the full extent of Karbaat’s dodgy behaviour wouldn’t come to light until after his death in 2017.

When the 89-year-old died two years ago, dozens of people came forward claiming to be his offspring. The group, which would become known as the ‘Karbaat children’, alleged the doctor had illegally used his own sperm to impregnate their mothers without their consent.

As The Guardian reports, some of the children looked nothing like their apparent donors and instead bore a striking resemblance to Karbaat.

On hearing about the claims, Karbaat’s widow initially denied access to his DNA, which was locked in a safe. The group then took legal action against Karbaat and the now defunct clinic and a judge ruled that they should have access to the DNA for paternity testing.

Later when DNA tests were conducted, 49 of the children conceived through the clinic were confirmed to be Karbaat’s own offspring.

“The results confirm serious suspicions that Karbaat used his own sperm at his clinic,” the Defence for Children organisation said.

While he was alive, Karbaat often referred to himself as a “pioneer in the field of fertilisation”, and he even admitted to using his own sperm to father around 60 children. The doctor also said he sometimes mixed his own semen with donor semen.

Joey, one of the ‘Karbaat children’, said he could finally move on with his life now that it’s been confirmed that Karbaat was his father.

“After a search of 11 years I can continue my life. I am glad that I finally have clarity,” he told Dutch broadcaster NOS.

Eric Lever, another one of Karbaat’s biological children, said he felt no resentment towards his father despite his deception.

“I don’t get the feeling that he cheated my mother,” he told the NRC Newspaper. “She really wanted a child and could not have one with my parental father.”

Joey and Eric are among the 49 people who have just discovered they have at least 48 half siblings.