A Dutch fertility doctor used his own sperm to inseminate female patients who gave birth to 49 children, DNA tests have confirmed.

Jan Karbaat, who died in 2017, has long been suspected of using his own semen at his now closed Rotterdam fertility clinic without the knowledge of the women. The doctor had repeatedly told patients that the sperm came from anonymous donors.

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Results of DNA tests "showed that 49 children in the case are direct descendants of the late Karbaat," the organization Defence for Children said on Friday.

"The results confirm serious suspicions that Karbaat used his own sperm at his clinic," the organization representing parents and children born through his clinic said Friday.

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The doctor's widow had refused to allow the use of his DNA samples, but a Dutch court in February allowed a genetic comparison.

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Before his death at age 89, Karbaat admitted to having used his own sperm to father about 60 children at his fertility clinic, which closed in 2009 due to reports of irregularities.

He also admitted to mixing his sperm with that of other donors.

Defence for Children said it was likely that Karbaat was the biological father of more than 49 children.

"Sperm belonging to the late doctor was also distributed to other clinics," the organization said.

Defence for Children adviser Iara de Witte said that after years of uncertainty, the parents and children "can finally close a chapter and start processing the fact that they are one of Karbaat's many descendants."

One of the children, Eric Lever, recently told the NRC newspaper he was "not angry with Karbaat."

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

cw/rc (AFP, dpa)

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