Screening is important at an older age before having a child: older men have semen that is more “contaminated” by mutant cells.
A research team has just discovered that older men are more likely to pass on genetic mutations to their children.
The genomic sequencing studied by the team revealed that, among men in their thirties, around 1 in every 50 sperm has a disease-causing mutation – a number that rises to almost 1 in 20 by age 70.
“The study clearly shows that older parents have a greater risk of transmitting more pathogenic mutations,” says Raheleh Rahbari, a researcher at the Wellcome Sanger Institute in the United Kingdom, to
“It’s something families should consider when making their own decisions.” For example, younger men may consider freeze sperm if they believe they will only have children later, suggests the researcher.
The explanation lies in the so-called “selfish sperm”: certain mutations can cause these stem cells to proliferate more than normal, exponentially increasing the proportion of sperm with these mutations as men age, rather than a gradual increase.
The one published in Nature this month identified a wide variety of mutations in more than 40 genes that make sperm stem cells selfish. “The overall effect on the genome was much greater than any of us thought“, says team member Matthew Neville.
“We have known for a long time that being an older parent is not ideal,” says scientist Anne Goriely. “Before, attention was really associated with the mother. Now we understand that both parents contribute to the health of their children“.
