The American Medical Association has returned the issue of sperm donor screening to the public eye after publishing an article detailing the transmission of a rare and deadly heart defect to nine offspring of a registered sperm donor. The Los Angeles man (42), who is the genetic father of twenty-four children, was given a full medical check, along with tests for infectious diseases and provided a full medical history when he originally donated in the early 1990s but his genetic condition was not diagnosed until one of the children, aged 2, died suddenly from a previous undiagnosed heart problem.

The condition, hypertrophic cardiomyopathy, leads to a thickening of the tissues in the heart, reducing the ability to pump blood. The problem affects around one in 500 people but, according to Dr Heidi Reim of Harvard Medical School and co-author of the article, many more are likely to carry the genetic defect without apparent symptoms.

The San Francisco sperm bank that passed the sperm on has now begun testing all donors with an electrocardiogram to ensure that transmission does not occur again. The article suggested that all clinics should consider implementing such a test as part of the battery of tests each donor engages in. While testing of donors is covered only by voluntary guidelines intended to rule out transmission of infectious and heritable diseases the degree to which genetic conditions are tested for varies widely and is often for rarer, higher profile conditions than hypertrophic cardiomyopathy.

If diagnosed, the condition is treatable through medication, surgery and the implantation of a defibrillator to restart the heart if it stops. Such surgery has now been performed on one of the afflicted children who was already symptomatic and the others are in receipt of regular observation to monitor their condition's development.