Recent reports of an error in ICSI treatment

18/12/2025

Following recent reports of the mix-up of sperm samples in 1994, UZ Brussel acknowledges that an error occurred, whereby a sperm sample from another prospective father was used for the family’s ICSI procedure. We acknowledge the error, which presumably occurred in the laboratory’s workflow.

We realise that this has had a profound impact on the family’s life and understand the feelings this entails. We are cooperating fully and are doing our best to answer their questions, taking into account the regulations on privacy and medical confidentiality of all parties involved.

We understand that this story may also raise questions among other prospective parents who have been treated at UZ Brussel. There is no indication that a similar error has occurred at our centre.

Over the years, UZ Brussel has continued to evaluate and adapt its patient identification procedures. Since 2011, we have been using the electronic witness system, which makes every step traceable and verifiable, to ensure 100% certainty that every egg, sperm and embryo belongs to the right prospective parents at all times and in all circumstances.

Prospective parents or children who have questions about their journey or parentage can contact us at afstamming@uzbrussel.be.