A fertility clinic in Leiderdorp knowingly used the sperm of mass donors for more than a decade, in breach of national guidelines, affecting hundreds of families, according to an investigation by Nieuwsuur.

Between 2006 and 2017, the Medisch Centrum Kinderwens (MCK), one of the largest fertility clinics in the Netherlands, used sperm from 36 donors far beyond the legal limit of 25 children per donor. In total, more than 1,200 children and over 900 mothers have been affected.

Junior health minister Vincent Karremans (VVD) described the practice as “appalling” and said it was “impossible to justify” keeping the families involved in the dark. Whether laws were broken will be determined by the health and youth care inspectorate IGJ.

The current management of MCK confirmed the breaches but blamed them on a policy introduced by the clinic’s previous directors which derived from the “shortage of donors, high demand from prospective mothers and the wish to have siblings from the same donor.”

The 25-child limit was set in 1992 to reduce the risk of half-siblings unknowingly entering relationships and to ensure donors could maintain reasonable contact with their offspring. Clinics can only exceed the limit in exceptional cases and with full consent from those involved.

MCK instead asked donors to sign contracts agreeing to donate to 25 families, a practice that significantly increased the number of children born. Some donors have since fathered up to 50 children in the Netherlands and abroad, Nieuwsuur reported.

‘Irresponsible and reckless’

The donors themselves were unaware that this practice was against the rules. “No donor we spoke to was told the rules were being breached,” donor association Priamos said. “Donors should be able to trust that clinics act properly.”

Parents were also unaware that the sperm used had been linked to far more children than allowed.

The Donorkind foundation, which supports the children of sperm donors, described MCK’s actions as “criminal child trafficking”. “Prospective parents were treated as paying customers, donors as raw material and donor children as products,” a spokesperson told Nieuwsuur.

Although the current MCK management ended the practice in 2017, it chose not to inform affected donors or families, and did not report the breaches to the inspectorate.

Calls are now growing for an independent inquiry into fertility clinic practices.

Last November, Leiden University’s teaching hospital LUMC confirmed that its former sperm bank was beset by administrative problems and that 440 people have more than the legally permitted 25 half brothers and sisters.

In total, the research shows sperm from nine donors was used more than the agreed 25 times and that one man has fathered 86 children. Some brothers and sisters, it has also transpired, have different fathers.  

Doctors

In 2022 the Donorkind foundation said it had identified at least 10 doctors who had illegally used their own sperm to create children in the Netherlands.

Among the high-profile cases involving fertility specialists are that of Jan Karbaat, who fathered 81 children at the last count, Jan Wildschut who fathered at least 47, and Jos Beek who has at least 21.

In April 2023, Dutchman Jonathan Jacob Meijer, who is thought to have fathered hundreds of children via sperm donation, was ordered by judges to stop the practice immediately. He was the subject of a recent Netflix series.