Hey blokes, if you want to have kids, get on with it. Your biological clock is ticking

Australia’s fertility rates aren’t anything new. In fact, rates have been falling since The Australian Institute of Family Studies was established in 1980.

A lot of time has been spent looking into and considering the reasons women are choosing to have fewer children than the generations before them, but as a reproductive endocrinologist and fertility specialist I can tell you that declining birth rates are as much about male fertility as they are women’s.

Male fertility is a huge factor in the chances of conception, but most people don’t realise this.Credit: Louise Kennerley

Today, one in six couples will struggle to have a family. And for 50 per cent of heterosexual couples who need interventional help such as IVF to conceive, a serious contributing factor is related to the health of a male partner. In 30 per cent of infertile couples, no female fertility barriers are present – the cause of fertility struggles are entirely related to male factors.

Sperm does not exist in a vacuum. A proportion of sperm problems are genetic and would affect a person at any age but advancing age, environmental, diet and lifestyle factors, and medical conditions are all major contributors to male infertility.

Putting on weight, smoking, drinking, medications for anxiety, depression and hair loss prevention, and the chemicals in common household cleaning products, deodorants and plastic containers around the home can all impair male fertility either by reducing the quality of the sperm, causing erectile dysfunction or reducing libido. Yet so much of what we talk about when it comes to fertility relates to the woman. The woman’s age, the quality of her eggs, her health conditions, her lifestyle choices.

Globally, we have seen falling sperm counts over decades of modern living, associated with increases in presentations of male factor infertility. But two things we know for sure is that younger men have better sperm and that men are delaying fatherhood until their later years.

The myth that the fertility cliff doesn’t exist for men is just that: a myth. Delaying fertility for males (as well as females) can seriously jeopardise a couple’s chances of having a healthy baby. Studies show that in instances where the father is aged over 35, a pregnancy is significantly more likely to end in miscarriage than those aged under 35. The risk for gene mutations that can cause conditions like achondroplasia and multifactorial conditions such as autism spectrum disorder and schizophrenia are also higher in older fathers. At a deeper level, there’s also evidence to show DNA fragmentation increases with age, which provides the opportunity for DNA errors to creep into the stem cells over time.

Just like their male counterparts, we know that women are also having children later in life, and it’s a well appreciated fact that natural fecundity (the chance of a female becoming pregnant per month) declines significantly after the age of 35.

In the 1980s, the majority of first-time Australian mums were giving birth in their early 20s. By 2021, the average age had shifted by an entire decade, with her now being aged 32.2 years at the time of her first birth.

And while most people want children, the reality is that very few understand the basic cold-hard facts about natural fertility. In 2018, I led a research team that surveyed 1215 male and female university students. Fewer than 10 per cent said they didn’t want to have children. Of the 90 per cent who said they did want kids, 75 per cent wanted two or more. Of that same cohort, who also hope to achieve a number of other life goals before turning their minds to parenthood, 95 per cent underestimated the impact age has on male fertility, with some completely unaware of the issue at all.

Medical advances have made having children later in life possible in a way that didn’t exist 50 years ago, and it’s something that should be celebrated. But the issue of why people are delaying parenthood isn’t a medical one, it’s social.

There are many reasons people experience infertility that have nothing to do with ageing. But as a specialist, I can swear with my hand on my heart that many couples who need help to conceive might not have struggled had they, like their 1980s counterparts, planned and started their family a decade earlier. That’s easy to say, but it’s also infinitely harder to fix. Because just like the myriad of reasons people may experience infertility, the same number of reasons exist as to why both men and women are having children later in life. But one guaranteed step that would likely improve the issue is general education about all fertility – female and male.

Dr Raelia Lew is a fertility specialist and director of Women’s Health Melbourne.

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