Time waits for no man: the impact of age on male fertility

It's a first for the Progress Educational Trust (the charity that publishes BioNews) – an event dedicated solely to male fertility: 'Time Waits for No Man: the impact of age on male fertility'. 

'When thinking about age, human biology predates any gender discrimination,' Sarah Norcross, Director of PET reminded the audience, who gathered last week in the ornate space of the Royal College of Physicians in Edinburgh. While women have a biological cut-off point for fertility – the menopause – no such point has been defined for men.

Consequently, the topic of age and male fertility lags behind in policy, scientific research, and public perception. Inspired by a 2015 paper recommending that all men should freeze their sperm at 18 (see BioNews 808), this event was a significant step towards addressing these imbalances.

The chair of the British Fertility Society, Dr Jane Stewart, kept each speaker to a strict eight minutes before opening the floor to questions.

First to speak was Professor Allan Pacey at the University of Sheffield, who outlined the difficulties of data on male age and fertility: namely that there isn't enough, and getting more requires complex and expensive studies. While some 2-3 million women and men experiencing fertility issues at any one time, he said studies typically measure live births and neglect to investigate male age. In his opinion, the best investigation to date is a 2000 study of 8500 couples by Bristol University researchers, which found men over 40 years old were half as fertile as men under 25.

Yet there have been no other comparable studies since. The closest, a 2006 analysis (see BioNews 318) which found sperm concentration did not decline with age, but sperm quality did.

And this lack of data often means we don't talk about parenting with equality, he pointed out. Older fathers are often celebrated in the media, yet older mothers are criticised.

Professor Chris Barratt, at the University of Dundee, delivered his message with help from Marlon Brando, Tom Cruise and Keith Richards. '[Nowadays], we don't always see ageing in the same way,' he mused, against a backdrop of pictures of young Brando and white-haired Brando, versus an eerily similar younger Cruise and older Cruise, versus an unchanging crease-faced Keith Richards. Somatic cells age, and perception of this ageing may be modifiable. But germ cells are ageing too, and this impacts the quality of gametes produced.

Professor Barratt ran through studies from Australia, the USA and the UK which showed a rise in the median age of fathers over the last two decades. With an ageing population, by 2100 there will be an extra billion adults aged 25-40 years old. We will see more older fathers, and this is going to compound problems, he warned.

The next speaker, Professor Richard Sharpe, principal investigator at the University of Edinburgh's Centre for Reproductive Health, discussed testosterone changes. Testosterone is important to sperm production and naturally declines with age, though this varies from man to man. Men with low testosterone are also more likely to have health problems, including obesity, cardiovascular disease and diabetes.

But studies have shown men born more recently have lower testosterone levels. Could this be related to why sperm counts have also fallen over the last 70 years (see BioNews 911)?

'And let's not forget the new kid on the block – epigenetics,' he said, referring to recent evidence of how genetic changes can be passed onto the embryo, making the impact of male age on infertility an even more multilayered issue.

Providing a clinician's view, the final speaker was Dr Sarah Martins da Silva, a consultant gynaecologist at Ninewells Hospital and Medical School. Female fertility is closely scrutinised when couples come to fertility clinics, or when NHS funding policy is under consideration. But the influence of paternal age is little discussed. For example, most of the public are unaware that it takes five times longer to achieve pregnancy when the father is over 45.

She highlighted studies associating higher paternal age with higher risk of early pregnancy loss and preterm birth, as well as complex mental disorders like schizophrenia, and autistic spectrum disorder. Older men also tend to partner with younger women, masking the effects of advanced paternal age.

Dr Martins da Silva suggested clinicians could add male and female age together when considering options of fertility treatment. She emphasised male age needs to be integrated into fertility policy, but this is challenging without consensus on what constitutes 'advanced paternal age'.

The talks had fertilised questions. Could environmental pollution be the cause of falling testosterone levels? Professor Sharpe said he was far less convinced of that hypothesis than he had been at the start of his career.

Currently some regions of the UK offer sperm banking for males whose fertility could be impacted by medical treatment. But should all 18 year olds freeze their sperm?

'Crackers,' remarked Professor Pacey (again, see BioNews 809), saying it was far from a simple or inexpensive process, and would balloon NHS debt – better to spend the money on a fertility education programme for men. He also cautioned against setting hard age limits on male fertility. There are always exceptions to the rule, nor is there sufficient data to do so.

Sarah Norcross asked what we could or should do now about male infertility?

Look at it from a future standpoint, urged Professor Barratt. If we have consistent results now, why aren't we doing anything about it? Currently all men are offered is storage. There have been no new male fertility treatments since ICSI (intracytoplasmic sperm injection) was developed in 1992.

Professor Sharpe said the focus on women had also created the mindset that male infertility is an unsolved problem, when it is actually a problem not yet looked at.

PET is grateful to the Scottish Government for supporting this event.

PET's next free-to-attend event supported by the Scottish Government will be 'From Acupuncture to Yoga: Can Lifestyle Choices Improve the Odds of IVF Working for You?', taking place in Glasgow on the evening of Thursday 14 June.

See here for further details, and email sstarr@progress.org.uk to book your free place.