Delayed fatherhood: the pros and cons of starting a family older

Scientists say men need to keep a close eye on their biological clock, just like women. We look at the risks and advantages of becoming an older dad

Pic: iStock

They are what news outlets throughout the world have fondly christened the Hollywood Older Dads’ Club. A cohort of famous septuagenarians and octogenarians who have welcomed or are planning to welcome babies in their twilight years.

Familiar faces from the “club” include legendary Mick Jagger, Clint Eastwood, Jeff Goldblum, and, most recently, the beloved Godfather co-stars Robert de Niro and Al Pacino.

Public reactions to such news often include a flurry of questions and comments, mostly rooted in a grim but inevitable biological reality. “There’s a higher probability that a child who has an 80-year-old father at birth is not going to see that father for their 21st birthday versus, say, a 35-year-old father,” says Dr Gloria Bachmann, co-director of the Women’s Health Institute at Rutgers Robert Wood Johnson Medical School in New Jersey in the US. “You may not be able to see that child develop through all the developmental stages because your risk of mortality increases, especially if you’re hypertensive, you’re diabetic, you have liver disease — all the things that come with ageing.”

Robert De Niro attending the 73rd British Academy Film Awards held at the Royal Albert Hall, London.

De Niro, who is 79, will be the ripe age of 97 by the time his daughter graduates from high school, while 83-year-old Al Pacino will have just turned 101. The Hollywood old-timers echo what is a global, albeit more muted, demographic trend toward having babies later in life.

In the US, the average paternal age has risen from 27.4 in 1970 to 30.9 in 2017. While the CSO does not collect data on the average age of first-time fathers, the Office for National Statistics (ONS) in the UK has revealed that the average age of new fathers is 33.7 years — an increase of 3.4 years since data collection began in 1964.

As the average paternal age in richer countries increases, other risks exist beyond the inevitable loss of parenting years. There is the historically overlooked matter of the male “biological clock”. Although the biological clock encompasses a set of concerns long associated with women, men also experience significant declines in fertility as they age.

While there is no age limit for the production of sperm, research shows that the quality of men’s semen declines as they age. “By about the age of 40, the health risks [for babies born to older dads] are roughly double those of a 25-year-old,” says Utah-based urologist Dr Jim Hotaling, the co-author of a comprehensive review of the fertility research published in the journal Fertility and Sterility last year.

This, according to Bachmann, is mainly due to an increase in DNA mutations, which have the potential to be transmitted to offspring. “The cells naturally undergo ageing so that there may be some chromosomal abnormalities, as well as a decrease in sperm count,” she says.

According to a 2019 review of the research co-authored by Bachmann for the journal Maturitas, infants born to fathers over 45 are at higher risk of low birth weight, premature birth, and seizures. Bachmann and colleagues also highlighted an association between what researchers call advanced paternal age (APA) and childhood cancers, such as leukaemia and non-Hodgkin’s lymphoma.

Caution urged

Concerning as these findings are, how do the risks translate into actual numbers?

The year before Bachmann’s review, a landmark study by Stanford researchers proffered an answer to this question based on data from more than 40m live births in the US between 2007 and 2016. Scientists found that babies born to fathers aged 45 and above had a 14% higher likelihood of premature birth and an 18% higher probability of experiencing seizures than fathers in the 25-34 age range. They also found that female partners of men over 45 were 28% more likely to develop gestational diabetes than their female counterparts with partners aged between 25 and 34 years.

Dr Tim Dineen

Although such observations remain sobering, Dr Tim Dineen, a male fertility expert at Waterstone Clinic, says there is uncertainty surrounding the robustness of the studies conducted to date. “Many of the studies [on male fertility] are built more on anecdotal suggestions as opposed to concrete evidence,” he says. “Even in cases of much older men becoming fathers, there’s a theory that a good-quality egg from a younger female partner can compensate for poor-quality sperm. So, if you’ve got a good-quality egg, there’s still a good chance of fertilisation, implantation, and ending up with a live birth.”

Balancing a sense of cautious optimism, Dineen highlights the importance of acknowledging the well-established link between APA and other psychiatric and neurocognitive disorders. Among them are autism spectrum disorder (ASD), obsessive-compulsive disorder (OCD), and schizophrenia.

In one commonly cited study of more than 87,000 infants born in the 1960s and 1970s, Swedish researchers estimated that the risk of schizophrenia increased from one in 141 for fathers aged 25 and younger to one in 47 in fathers aged 50 and above. Hotaling puts it succinctly: “After reaching the [paternal] age of 25, autism and schizophrenia risks increase by 4% each year.”

Nevertheless, Dineen urges caution when interpreting the data, saying, “These [ASD, attention deficit hyperactivity disorder (ADHD), and schizophrenia] are conditions where there isn’t a direct genetic link. There are a number of factors involved as opposed to it being a single one [or a simple causal relationship].”

Minimising risks

Armed with an understanding of the risks, what can older would-be dads do to minimise them? The options available are limited, according to Hotaling and Bachmann, unless you can afford to pay for sperm freezing or in vitro fertilisation when the time comes.

Dineen, who remains sceptical about the necessity for sperm freezing as a mainstream intervention, suggests that lifestyle factors can have a modest but significant impact.

“While there is no magic bullet and effects can be quite difficult to quantify, there is value in making sure you have a healthy diet, taking supplements like zinc and magnesium, and cutting down on your intake of alcohol and caffeine.”

Risks aside, Bachmann reminds us that good parenting has little to do with age. In fact, it seems that being an older dad can come with some notable benefits, an increase in free time being one of them.

“A lot of older dads aren’t as focused on their professions as they might have been in younger years,” observes the obstetrics and gynaecology specialist.

“I think, if you make that choice to have kids at an older age, you have probably achieved what you wanted to achieve professionally, and you may have more time to devote to parenting.”

Reaching this stage of professional advancement may also come with greater financial stability. Hotaling says: “Demographic data indicates that children from older dads do very well, typically because the dads and their partners have more resources available for the child.”

There is no reason why older men cannot make great dads. For this reason, preconception counselling regarding the various risks should be provided to men as frequently as it is to women. Men, too, should remain mindful of their ticking biological clocks.