Khaberni - A new British study warns that men delaying fatherhood may have unexpected genetic consequences.
The study found that as men age, the likelihood of transmitting harmful genetic mutations from fathers to their children increases, a phenomenon which was previously thought to be specific to women only.
While the risks of older mothers giving birth have been known for a long time, due to poor egg quality and increased likelihood of chromosomal defects, the study reveals that this issue does not solely affect women, but also men.
Researchers from the Wellcome Sanger Institute in Cambridge tracked the DNA of more than a thousand sperm samples from 81 men aged between 24 and 75 years old.
The results showed that approximately one in every 50 sperm in men in their early thirties carried disease-causing mutations, while the rate increased to one in every 20 for men over forty up to seventy years old.
Dr. Matthew Neville, a computational biologist involved in the study, explained that the team was surprised by the magnitude of increase in sperm carrying serious mutations, noting that some of these mutations "thrive in the testes" thanks to a type of natural selection that gives them a reproductive advantage.
The forty genes studied included mutations linked to disorders such as autism and certain types of cancer.
According to Professor Matt Hurles, director of the institute and co-author of the research published in the journal "Nature", the results "reveal an hidden genetic risk that increases with the father's age," adding that men who father children at an older age might transmit harmful mutations unknowingly.
Statistics indicate that sperm counts are declining globally, having decreased by 60% in just one generation, while the annual decline rate has doubled since the year 2000.
Additionally, young people today are three times more likely to have fertility issues compared to previous generations.
The researchers emphasize that these mutations do not necessarily lead to conception or birth, as they may hinder fertilization or cause miscarriages, but their increase with age calls for a reevaluation of the timing of fatherhood.
It is noted that men produce new sperm throughout their lives, but their quality declines with age due to subtle chemical changes within the body.
While some Western health systems only offer sperm freezing services for medical reasons, some private clinics provide this service for an annual fee of approximately 300 British pounds, an option that might help those who want to maintain their fertility at an earlier age.
