Brussels fertility clinic investigated for exceeding donor limits

Authorities have launched an investigation, after a sperm donor carrying a cancer-linked mutation was discovered to have fathered over 50 children via Belgian fertility clinics.

In June 2025, the Belgian Federal Agency for Medicines and Health Products confirmed that sperm from a single donor was used for at least 39 women across three or more clinics in Belgium, surpassing the six-woman limit set by Belgian law. The donor's sperm carried a mutation in the TP53 gene, linked to Li-Fraumeni syndrome, a condition which increases the risk of cancer at an early age. The Brussels Prosecutor's Office launched an investigation into one of the clinics involved, which has now been named by public broadcaster VRT as the UZ Brussel fertility clinic.

'In the context of the recent problems with the national violation, we were contacted by the public prosecutor’s office with a request for clarification,' a statement from UZ Brussel said. 'We are cooperating in a spirit of complete transparency.'

Belgian law limits the use of sperm from a single donor to six women, and a central donor database came into operation in January 2024. Before this, clinics could only check their own records, creating a regulatory gap that allowed breaches across multiple centres. It is not yet known whether other Belgian clinics will face investigation.

According to Euronews, the investigation in Belgium concerns the same sperm donor linked to the births of 67 children between 2008 and 2015 across eight European countries (see BioNews 1291). Findings presented at the European Society of Human Genetics' annual conference in May 2025 revealed that ten of these children had developed cancer, and at least 23 carry the genetic variant. The sperm was donated via the European Sperm Bank (ESB) in 2008, however the genetic variant was of unknown significance at the time.

UZ Brussel announced this week that it was ending its partnership with ESB, due to these issues. Another centre in Antwerp reviewed its collaboration with ESB but has not yet ended the partnership.

These revelations highlighted the challenges of cross-border sperm banking and fragmented oversight. Many European countries limit the number of children or families that can be created using a single donor. However, these limits are not necessarily imposed across Europe, and some experts have suggested that international limits on use of donor gametes are needed (see BioNews 1240 and 1241). Earlier in 2025, the four Nordic National Ethics Councils called for international regulation of sperm donation, in part due to increased international use of large commercial cryobanks (see BioNews 1283).