New Zealand's largest network of fertility clinics will no longer accept sperm donors over 45 after research linking older fathers with a range of conditions in children including schizophrenia.
A Fertility Associates newsletter refers to a British/Swedish finding that the children of fathers over 50 are three times more likely
to develop the mental disorder than those of fathers under 30.
It says: "The underlying mechanism is thought to be due to spontaneous mutations in the father's DNA.
"Older fathers are also slightly more likely to have children with Down syndrome, particularly when combined with older mothers...dwarfism also increases with ageing dads, as does acute lymphocytic leukaemia."
British and American researchers also found an association with autism. Among fathers in their 40s when a child was born, the risk of the children developing autism was more than five times greater than for children of men under 30.
The director of Fertility Associates, Dr Richard Fisher, said yesterday that the absolute risk of developing any of these conditions was small, but the evidence was mounting of the relatively greater risk for children of older fathers.
"We want to ensure things are as safe as possible."
Previously the age limit was 50 for men in the clinic's pool of sperm donors.
But Dr Fisher said individuals who came with a potential donor over 45 would still be able to use the man's sperm but would be advised of the greater risks.
The change has made recruiting donors even more difficult. In Auckland, Fertility Associates has more than 100 couples or single women waiting for a sperm donor.
Dr Fisher said the clinic had only 10 or 20 donors on its books - none was over 45 when the age was lowered - but the pool had been augmented by one or two by a change in March: The admission of gay men.
Previously the clinic barred gays from its general donor pool because they were considered at greater risk of carrying HIV.
But after a challenge from a gay man and a visit from the Human Rights Commission, the clinic realised new guidelines issued last year allowed it to set its own risk parameters.
