The owner of a fertility clinic used his own sperm to father 49 children, according to DNA tests revealed on Friday.
Jan Karbaat, who died two years ago, impregnated their mothers at his clinic near Rotterdam, in the Netherlands.
Jan Karbaat, who died in 2017, has always been suspected of using his own semen at his now closed Rotterdam fertility clinic without the knowledge of the women.
None of the women were aware he was using his own semen instead of their chosen donor's.
DNA tests were conducted yesterday and they confirmed that 49 children in the case are direct descendants of Karbaat.
Suspicions first arose in 2017 when parents and children who were treated at the clinic in Bijdorp, near Rotterdam, took Karbaat to court over concerns they were related.
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.
The controversial case became public after a Dutch court ruled in February that the results of Karbaat's DNA test should be made available to parents and children to conduct their own comparisons.
He said he had sometimes mixed his sperm with that of other donors.
Iara de Witte, an adviser at Defence for Children, said: "The judge placed the interest of the child above the right to privacy of Mr Karbaat and his family".
One of the children, Joey, spent the past 11 years searching for answers and told Dutch broadcaster NOS he was "glad to finally have clarity".
Defence for Children said it was likely that Karbaat was the biological father of more than 49 children.
It also said it was pleased that "the years of unrest and uncertainty that the late Mr Karbaat" caused had "finally come to an end".