Alec Baldwin, Richard Gere, Steve Martin - it seems every man in Hollywood over the age of 60 is having babies.

The spate of older celebrity dads matches a narrative that we have as a society. Women, we know, run into trouble conceiving in their mid-30s while men can seemingly keep going forever. It is true that male fertility has a longer shelf life but the idea that all men can easily have kids into their 70s just isn't true. Men much younger than that are now struggling to become dads.   The facts A 2017 scientific review found that sperm counts declined by 52.4 per cent between 1973 and 2013 in the West. It's a factor that's often overlooked when a couple is struggling to conceive, says Dr Simon Fishel, founder of Beacon CARE Fertility "We know that men are the cause of up to 40 or 50 per cent of all infertility," he tells us. The reason for this, he says, is the same as the reason we so many women struggling - age. Men are waiting longer to start their families and lots are surprised to find that they have trouble when they do start to try. Failing to conceive isn't the only issue - delaying fatherhood is associated with a number of health issues for their children, according to Dr Fishel.

"We also know men have a biological clock," he says. "A man’s biological clock is a little more insidious. Women’s is overt – they’re either having a problem getting pregnant or they’re having miscarriages. "A man’s is slightly different. There have been links to leukaemia, for example, to autism, for example, in children being conceived by older men."

Indeed, a 2011 study found that the risk of autism in children was 28 per cent greater among dads in their 40s  and 66 per cent greater among dads in their 50s, compared to men who had become fathers before 30. Other associated issues include breast cancer, epilepsy and achondroplasia, a disorder that causes dwarfism.   What to do? Men are advised to start trying before 4o but there are other things to bear in mind. "We know that simple lifestyle changes can also boost a man’s fertility considerably," Dr Bart Kuczera from Beacon CARE Fertility said earlier this year. To be on the safe side men should eat a healthy diet, limit drinking and avoid smoking. They should also avoid anything that could cause their groin to heat up, including:

• sitting still for long periods of time, particularly when driving long distances
• hot baths and saunas
• using a laptop on your lap
• wearing tight underwear
• working in a hot environment, such as a kitchen or bakery

Something else men can consider, Dr Fishel says, is sperm freezing. It's a simple process and a lot cheaper than egg freezing but could ensure that a man gets to become a father and that his future children are healthier.   This October is Fertility Month on Her, when we’ll be talking all things reproductive health and having babies.  You can check out all of our Fertility Month articles here. Want to get in touch? Email me at anna@her.ie.