Shocking! Scarwave in Europe after donor with cancer gene fathers nearly 200 children

New Delhi: A far-reaching investigation across Europe has uncovered a disturbing case involving a sperm donor whose genetic mutation has left dozens of families facing the possibility of childhood cancer. The man, who began donating in Denmark nearly two decades ago, has fathered at least 197 children in 14 countries, unknowingly passing on a mutation in the TP53 gene — a defect associated with Li-Fraumeni syndrome, one of the most aggressive hereditary cancer conditions known.

The scale of the case only became clear after doctors in several countries began comparing notes about children with unusual cancer histories who shared the same donor number. Their findings were later expanded by a collaborative investigation involving 14 public broadcasters, including the BBC. While the donor’s sperm was never sold to UK clinics, a small group of British women travelled to Denmark for treatment and used the same donor’s samples. Those families have now been contacted.

The donor himself appeared healthy and had passed standard screening when he began donating as a student in 2005. What doctors later discovered was that the harmful mutation existed only in a fraction of his cells — a condition called "mosaicism” — meaning it went entirely undetected during routine checks. Roughly 20 per cent of his sperm carried the faulty TP53 gene, but any child conceived from those affected sperm would inherit the mutation in every cell of their body.

Li-Fraumeni syndrome gives patients a lifetime cancer risk of up to 90 per cent. Many of these cancers strike in childhood and adolescence, ranging from soft-tissue tumours to brain cancers and early breast cancer. "It is a dreadful diagnosis,” said Prof Clare Turnbull of the Institute of Cancer Research, describing the lifelong anxiety and treatment burden families face. Children with the condition typically undergo annual whole-body MRI scans, brain screenings and, in some cases, preventative surgeries.

The European Sperm Bank, which supplied the donor’s samples, expressed its sympathy to affected families and acknowledged that the donor’s sperm had been used far more widely than intended in some countries. In Belgium, where the regulatory limit is six families per donor, the man’s sperm resulted in children for 38 different women — more than six times the permitted number.

The investigation has so far identified at least 197 children conceived using the donor’s sperm, though the number could increase as more clinics release data. It remains unclear how many of these children inherited the dangerous mutation. Some children have already died, and others have survived multiple cancers. Dr Edwige Kasper, a cancer geneticist in France, said her team had encountered children who had developed two different cancers before reaching adulthood.

For parents, the discovery often arrives years after their child’s birth. Céline — not her real name — learned the truth only after receiving a call urging her to have her daughter tested. The teenager carries the mutation. Céline holds no resentment toward the donor, but she is angry about the system that allowed the same sperm to be used so extensively. "It wasn’t safe,” she said. "And now cancer will always be somewhere in the background of our lives.”

The case exposes glaring gaps in international fertility regulations. There is no global limit on how many children can be conceived from a single donor, and countries’ rules vary widely. Experts say heavy reliance on large commercial sperm banks has made cross-border oversight increasingly complicated.

Prof Allan Pacey, a fertility expert in the UK, told the BBC that while the situation is tragic, no screening system can guarantee perfect safety. "You can’t screen for everything,” he explained, warning that tightening criteria further could leave countries with severe donor shortages.

The incident has renewed calls for stricter family limits and clearer international rules. Yet specialists also stress that such cases remain extremely rare and that regulated clinics still offer far more genetic protections than unmonitored conception.