Women are often all too aware of their biological clock, with it becoming increasingly difficult to conceive from around our mid-30s.
The likes of Mick Jagger, Rod Stewart and Hugh Hefner may have lulled men into a false sense of security that they can father a child at almost any age, with new research suggesting male fertility also drops off.
Scientists from London's Centre for Reproductive and Genetic Health analysed more than 4,000 men while their partners tried to become pregnant via in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI), when healthy sperm is injected into an egg in a laboratory.
Perhaps surprisingly, the probability of the fertility treatment resulting in a live birth dropped by a third (33%) among the men over 50, regardless of their partner's age.
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Writing in the journal Acta Obstetricia et Gynecologica Scandinavica, the scientists have warned "there should be a public health message for men to not delay fatherhood".
Sir Mick's eighth child was born in December, 2016 – when The Rolling Stones frontman was 73. Sir Rod similarly became a parent for the eighth time when his wife Penny Lancaster-Stewart gave birth to their son Aiden in 2011, when the Maggie May singer was 66.
Known for his tumultuous love life, Playboy founder Hugh Hefner became a father to Marston Glenn and Cooper in 1990 and 1991, when he was aged 64 and 65.
Overall, the average age of the fathers of babies born in England and Wales in 2017 was 33.4, up slightly from 33.3 the year before.
The quality of a man's semen, the fluid that contains sperm, is known to deteriorate with age. Nevertheless, evidence was "conflicting" when it came to "any impact paternal age may have on the outcome of IVF/ICSI".
Some studies have suggested an older father is linked to an increased miscarriage risk, while others showed no effect.
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With there being no limit on a father's age during IVF or ICSI treatment, the London scientists analysed more than 4,200 men while their female partners went through over 4,800 fertility cycles between them.
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Overall, two in five (40.8%) of the IVF or ICSI cycles resulted in a live birth. The probability of this occurring was 33% lower among the men aged over 50 compared to their younger counterparts.
Of the 133 men aged over 51, just 56 (42%) met "World Health Organization [WHO] semen analysis criteria", compared to 61% of their 4,138 younger counterparts. The WHO defines "quality" semen as containing 39 million sperm per ejaculate, as well as measuring their "vitality" and shape.
In the London study, an older father was not linked to a higher risk of a miscarriage.
"Paternal age over 50 significantly affects the chance of achieving a live birth following ART [assisted reproductive technology]," wrote the scientists.
"There should be a public health message for men not to delay fatherhood."
Watch: More older women are turning to IVF