London: Men who are planning to delay parenthood should think again, as a study has revealed that children of older fathers are more than twice as likely to be born with genetic mutations, which can lead to health problems.
Most fertility researchers focused on the impact of the mother’s age on children’s health, because sons and daughters of older women are known to be at higher risk of Down’s syndrome and other, rare disorders.
But the new study by DECODE Genetics, an Icelandic company and published in the Nature journal, has shown that most genetic mutations that arise in children are passed down by the father’s sperm rather than the mother’s eggs.
While the majority of mutations are completely harmless and lead to natural variety between people, some are responsible for diseases including autism and schizophrenia.
The study that include 219 Icelandic mothers, fathers and children found that the average woman contributes about 15 new mutations to her child through her eggs, regardless of her age.
But because sperm, unlike eggs, are constantly multiplying, they are more likely to develop imperfections, as the father gets older, at a rate of about two per year.
This implies that while a 20-year-old man passes on about 25 mutations through his sperm, in an average 40-year-old this will rise to about 65.
“All areas of the human genome were a mutation once upon a time, so all human variety is down to a mutation,” the Telegraph quoted Kari Stefansson, senior author of the study as saying.
“But one interesting aspect of this work is it shows us that the classic focus on the age of the mother and the health of the child is not sufficient.
“The increasing age of the father has a much bigger impact on a child’s health in a general way. Women are off the hook and we men are on it,” he added.