A recent study published in Nature has found that the age at which a father has children will determine how many mutations his offspring inherit.
Pioneering geneticist J. B. S. Haldane in the 1930s, had worked years before the structure of DNA was determined, but according to Nature, he was correct about why fathers pass on more mutations than mothers. “Sperm is continually being generated by dividing precursor cells, which acquire new mutations with each division. By contrast, women are born with their lifelong complement of egg cells,” according to the article.
The study found that fathers passed on nearly four times as many new mutations as mothers: on average, 55 versus 14.
Stefánsson’s team also found that the older a man gets, the more new mutations are passed on. “A 36-year-old will pass on twice as many mutations to his child as a man of 20, and a 70-year-old eight times as many,” his team estimated.
Since the average age of childbearing is rising, the study suggests that more children will be born with an increased number of mutations. Although the team says most mutations are harmless, some can lead to conditions such as schizophrenia or autism.