Men ought to freeze their sperm as young as 18 if they want to ensure having healthy children, according to a British bioethicist.
Writing in the Journal of Medical Ethics, Dr Kevin Smith from Abertay University in Dundee said although men are able to have children well into old age, leaving it too late can have health consequences.
As men age, their sperm becomes more susceptible to defects that can lead to disorders such as schizophrenia and autism.
This is becoming more of an issue as the average age for becoming a father rises across England and Wales, he said. In the early 1990s it was 31, but this has since risen to 33.
While the risk is small at the individual level, he argued the nationwide impact of men choosing to have children later in life could be significant. As such, he believes sperm banking at a young age in the UK should “become the norm” and be made readily available on the NHS.
"I think on a society-wide basis, we do need to worry about it - it is a very real and pronounced effect,” he told the BBC.
It's time we took seriously the issue of paternal age and its effect on the next generation of children.
So when should men turn to the sperm bank? Smith said there is no definite age, but suggests men in their 40s ought to consider this option.