A major investigation is underway after it was revealed that a sperm donor who unknowingly carried a genetic mutation linked to cancer risk fathered more than 197 children across Europe.

According to the BBC, several of the children born using the donor’s sperm have since passed away, while others who inherited the mutation may never develop cancer during their lifetimes. The discovery has sparked renewed concerns about international fertility regulations and donor screening practices.

How The Sperm Was Used

While officials clarified that the sperm was not sold directly to UK fertility clinics, some British families have confirmed they used the donor’s sperm while undergoing fertility treatment in Denmark. Denmark’s European Sperm Bank issued a statement acknowledging the situation and admitted that the donor’s sperm was used to conceive a large number of children in multiple countries.

The donor, who was a student at the time, was paid to donate sperm in 2005, and the samples were used for fertility treatments over a 17-year period.

The Genetic Mutation Explained

Further investigation revealed that the donor had passed all required screening checks. However, researchers later discovered that a mutation in the TP53 gene — which plays a critical role in preventing cells from becoming cancerous — occurred before the donor was born.

While the mutation was not present in the donor’s own body cells, nearly 20 percent of his sperm carried the damaged gene. As a result, children conceived using the sperm could inherit the mutation in their own body cells, potentially increasing their lifetime risk of developing cancer.

Global Impact

The sperm was reportedly distributed to 67 fertility clinics across 47 countries, raising concerns about how donor limits are enforced internationally and how genetic risks are monitored over time.

The case has led to calls for stricter global regulations, improved genetic testing, and clearer limits on how many families a single donor can impact.