A request by families seeking DNA tests of the late fertility clinic doctor has been approved by a dutch court. The doctor has been accused of using his own sperm in dozens of cases, instead of the chosen donor sperm.
Jan Karbaat is suspected of fathering about 60 children at the centre he ran in Bijdorp, near Rotterdam.
Tests will now be conducted on items seized from his home after his death in April, at the age of 89.
A lawyer for his family said there was no evidence to support the claims.
Jan Karbaat called himself "a pioneer in the field of fertilisation".
His clinic was closed in 2009 amid reports that he had allegedly falsified data, analyses and donor descriptions and exceeded the permitted number of six children per donor.
At a court hearing last month, a lawyer for the 22 parents and children said that the suspected cases included a client's child who had brown eyes when the sperm donor was supposedly blue-eyed and a client's son who physically resembled the doctor.
The DNA profile will remain sealed until the children can show there is cause to believe he is their father.
Eventually, if the DNA profile matches, the children, most of them born in the 1980s, hope to sue the doctor, possibly on the grounds that they should not exist, a correspondent added.
Joey, who believes Jan Karbaat may be his father, told the BBC: "It means everything to me... We hope to get the answers."
The Karbaat family's lawyer argued against any DNA tests taking place. While alive, the doctor himself refused such tests.
However, last month, Jan Karbaat's son donated his DNA for tests, which showed that the doctor could be the father of 19 children, born though IVF.