Over 400 people have more than 25 half brothers or sisters due to sperm donor fathers

An investigation into the lackluster administration at a sperm donor facility in Leiden has shown that 440 people have more than 25 half brothers or half sisters via the facility. It had already been reported earlier this year that the facilities administration, which was active from 1977 to 2004, was very disorganized.

Several biological fathers could not be found anymore, and it was clear that nine sperm donors had more biological children than the maximum requirement of 25. One of the donor’s seeds was used to conceive 90 children.

The Leiden University Medical Center (LUMC) looked into past events because the children who were conceived wanted to know who their biological father is. The LUMC also started a search at the beginning of this year for women who had gone to the facility because they wanted children

"The results of the research so far show that of the 1173 descendants, 440 descendants have more than 25 half-brothers/sisters. But it has also become clear that there is a lot we do not yet know or cannot find out. For example, it is not possible to determine from which donor the donor sperm was used for 102 descendants,” the LUMC now said.

The people involved have now been notified of the results of the research. “The people involved feel cheated,” the LUMC added. It realizes the significant impact its findings have, it wrote on its website. "We take our responsibility by being open as far as possible and thus providing as much clarity as possible to all those involved," said LUMC director Martin Schalij.

“The report also showed that there were clues before 2023 indicating that the administration was incomplete. We realize that with the knowledge we have now, we should have reacted to these clues to inform the people involved. We deeply regret that we did not do this,” Schalij said.

He pointed out that there are problems with other former sperm banks and repeated his call for a national investigation into the administration of other sperm banks.