Gynecologist used his own donor sperm to secretly father 41 children, not 21

Gynecologist Jos Beek from Leiderdorp fathered at least 41 children by secretly using his own sperm during fertility treatments, new research showed. It was previously thought that Beek fathered 21 children. The study also revealed that Beek carried a rare hereditary condition. Two of the children he fathered died from it, Omroep West reports.

The Alrijne Zorggroep asked an independent committee led by professor Didi Braat to investigate Beek after 21 donor children showed up at the hospital last year with DNA tests matching the gynecologist.

Beek died in 2019. He worked as a gynecologist in the former Sint Elizabeth Hospital in Leidedorp, which later became part of the Alrijne Zorggroep. He performed fertility treatments from the mid-1970s until 1990, not 1986 as previously thought. “The oldest (known) child was born in 1975, the youngest in 1990,” Braat said.

The women Beek treated asked to be inseminated with sperm from an anonymous donor. He used his own sperm instead without telling them. The researchers could find no record of sperm donors, leading to the suspicion that Beek was the only sperm donor at his practice.

The researchers also found that Beek carried a rare genetic disorder. One of the women he inseminated also had this gene, with severe consequences. “There was a mother who had two children after treatments by Beek, and both children died in the first year of life. When the second child died in 1990, the hospital did an invitation, and the genetic abnormality came to light,’ Braat said to the broadcaster.

“It is important for children to know this,” Peter Jue of the Alrijne Zorggroep’s board of directors said to Omroep West. The hospital again called on people to come forward if they were conceived with donor sperm, and Beek treated their mother. The hospital offers support to the children fathered by Beek. “As a hospital, we try to do everything we can to assist the children and the parents with the questions, doubts, and uncertainties they have,” Jue said.

For the study, Braat spoke to former employees and colleagues of Jos Beek and his widow. “Beek evoked strong and widely divergent reactions; there was no middle ground,” the report reads. “On the one hand, he was very involved with his patients and wanted to help them; on the other hand, he had enormous ambition and a penchant for prestige and considered himself a very suitable donor.”