A group of 22 people have won the right to have their DNA checked against that of a Dutch fertility clinic doctor who is feared to have fathered 200 children by using his own sperm rather than that of donors.

Jan Karbaat, who died in April 2017 aged 89, always denied the accusations and refused to cooperate with those potentially affected.

But a court has ruled that DNA tests can be undertaken as there is sufficient evidence to suggest Karbaat used his sperm without declaring it.

One of the children, Merel-Lotte Heij, said in response to the judgment that “every child has the right to know where he comes from”.

In 2017, 22 children who had been conceived with the help of Karbaat’s Blijdorp medical centre in Barendrecht, south of Rotterdam, and 11 of their parents, went to court to demand a DNA test.

The doctor died a month before the lawsuit and Karbaat’s family lawyer fiercely fought against any DNA checks, saying the privacy of the deceased and his relatives should be respected.

The judge felt at that stage there was insufficient evidence to allow the tests. The court only gave permission for Karbaat’s DNA, collected from 27 personal objects, including a toothbrush, to be secured in a safe.

Since the 2017 hearing, significant DNA links between a legal child of Karbaat and those conceived with his clinic’s help have emerged.

The court on Wednesday ruled that the interests of those who want to know if they are descended from the doctor outweighed the interests of Karbaat’s widow and heirs.

“If he did [use his own sperm], without announcing it at the time, his widow and other heirs cannot claim that the doctor’s anonymity should be respected,” the judge said.

It is feared that as many as 200 children may have been fathered by Karbaat. Clinical tests in 2017 suggested a high level of certainty about the paternity of 47 children.

Dutch children born to donors before 2004, when the law was changed, have no legal right to know the identity of their biological parent.

But the judge said the Karbaat case had special merit given the alleged illegality of the doctor’s actions. Dutch law limits the number of people who can be conceived from one sperm donor to 25.

The 2017 hearing had heard that Karbaat once reportedly boasted of fathering 60 children through IVF treatment.

When his clinic was shut down in 2009, major administrative irregularities were found. He is thought to have falsified data and the descriptions of donors.