When sperm starts to "spoil": scientists determine dangerous age for fatherhood
Kyiv • UNN
British scientists have found that with age, men pass on more harmful genetic mutations to their children. After the age of 30, the risk of mutations in sperm increases, reaching 1 in 20 at the age of 43-70.
Every day, the male body produces millions of sperm, but even the slightest change in body chemistry can affect them. In Britain, more and more men are choosing to freeze their sperm, a service that costs £300 a year, writes UNN with reference to the Daily Mail.
Details
While it was previously believed that the risk of a child being born with congenital defects only increased with the mother's age, it has now been found that late fatherhood also carries its own risks. British scientists from the Wellcome Sanger Institute in Cambridge have discovered that as men age, they pass on more and more harmful genetic mutations to their children.
The study showed that in men over 30, approximately one in 50 sperm have mutations associated with diseases. Between the ages of 43 and 70, this figure rises to 1 in 20.
Experts stated that the results "clearly" show that older parents have a "higher risk of transmitting more pathogenic mutations," and prospective parents should take this into account.
At the same time, numerous studies show that sperm count – an indicator of male fertility – is also declining worldwide, with some estimates showing a drop of as much as 60% in just over one generation.
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Thus, studies have shown that "until 2000, the average sperm count decreased by about 1% each year, and since then the rate of decline has doubled," the publication writes.
Scientists who studied more than a thousand sperm in 81 volunteers aged 24 to 75 found more than 40 genes in which changes occur with age that can increase the risk of autism, cancer, or developmental disorders.
Dr. Matthew Neville, a computational biologist at the Wellcome Sanger Institute in Cambridge and co-author of the study, said: "We were surprised by how much age increases the number of sperm carrying mutations associated with serious diseases."
Professor Matt Hurles, Director of the Wellcome Sanger Institute and co-author of the study, said: "Our findings reveal a hidden genetic risk that increases with paternal age."
Some DNA changes not only survive in the testes but also actively spread, meaning that fathers who conceive later in life may unknowingly have a higher risk of passing on a harmful mutation to their children.
Scientists emphasize that not all such mutations lead to the birth of a sick child – some may prevent fertilization or embryo development. However, the trend is alarming.
Scientists found that about 2% of sperm from men aged 30 and over contain disease-causing mutations. This proportion increased to 3-5% in men aged 43 to 74.
Among 70-year-old participants, 4.5% of sperm contained harmful mutations, indicating a clear link between age and genetic risk for offspring.
Addition
Unlike women, who are born with all the eggs they will ever have, men begin producing sperm between the ages of ten and twelve and continue to do so throughout their lives. The average man produces millions of sperm every day, which then take about three months to fully mature. But despite their ability to survive outside the body, sperm are surprisingly fragile.
Seemingly minor changes in body chemistry can have a profound effect on their ability to move, grow, and fertilize an egg. And any change in the number of sperm in a given amount of semen – the sperm count – can affect a man's ability to conceive a child.
The British National Health Service (NHS) does not provide standard sperm freezing services. This is usually only offered to men whose fertility may be affected by illness or treatments such as cancer therapy.
However, private clinics offer this service for £300 per year, plus the cost of infertility treatment when a man wants to use frozen sperm to fertilize a woman.