Sperm from donor carrying disease-associated gene variant used to conceive 53 children

Sperm from a Danish donor carrying a genetic variant classified as 'likely pathogenic' was used by 39 women in Belgium to conceive 53 children.

The donor carries a variant of the COL3A1 gene, which makes a type of collagen: a protein that gives strength and structure to blood vessels, skin and other organs. Belgium has a limit of six families per donor, meaning that only six women in the country should be able to become pregnant using sperm from the same donor.

The sperm was supplied by Danish sperm bank Cryos International, whose chief executive Ole Schou told newspaper De Standaard – which broke the story – that the donations go back to the 1990s, long before Belgium's family limit was introduced in 2007. Schou described this as 'a historical case, which is not representative of our current management of quotas'.

Two of the 12 Belgian clinics that received sperm from this donor exceeded the six-family cap, and the same sperm has also been distributed to further clinics across 24 countries.

The COL3A1 variant came to light after two donor-conceived children were found to have the variant, which is associated with the genetic condition vascular Ehlers-Danlos syndrome. Subsequent testing confirmed it was present in the donor's sperm, and the donor was subsequently blocked from further use by Cryos in July 2026.

The case is similar to an instance in which sperm from a different Danish donor, later found to be carrying a TP53 variant linked to an increased cancer risk, produced 53 children from 38 Belgian women from 2007 to 2017, before being blocked in October 2023 (see BioNews 1291). That donor's sperm reached 14 Belgian clinics, one of which inseminated nine women in breach of the six-woman limit.

Belgium has since reformed inspections and sanctions for fertility clinics, building on its Fertidata central donor registry launched in 2024, which lets clinics check the legal limit before using a donation.

The Belgian Federal Agency for Medicines and Health Products (FAMHP) has reported 121 breaches of the six-family rule since 2011; however, they added that the recent rise in reported cases reflects better detection rather than an increase in violations.

'Recent press reports show that such [instances where donor family limits are exceeded] are observed in several countries, which once again demonstrates the need for a European approach,' a statement from the FAMHP said.

'The creation of a European central donor register and the harmonisation of quotas applicable in the different Member States are essential tools to prevent quota overruns, [would] improve the traceability of cross-border donations and ensure confidence in and quality of medically assisted reproduction.'