It's hard to imagine that what a man eats, how he lives his life and the weight he's carrying can have an impact on his future children – but that's exactly what new research is finding.
As it turns out, conceiving a baby isn't just about fertility and women's health: a man's lifestyle can impact on the child's physical and mental health well into their future.
While one Australian study suggests a father's bad diet can impact on his child's mental health, recent research out of Denmark shows that a father's obesity can impact on his child's appetite and weight throughout their life.
"This is early evidence that sperm carries information about a man's weight," say the researchers.
While pre-conception health is often seen as the mother-to-be's responsibility, all this research shows that men need to take care of their own piece in the puzzle too.
Dr Andrew Davidson, Medical Director at City Fertility Centre on the Gold Coast, says that as there are two parents involved in conceiving, it's important that two people adjust their behaviours accordingly. "It's 50 per cent of the DNA coming from the sperm, so the male side of things is very important. We now have evidence that male lifestyle factors affect the quality of the sperm."
The ways in which men can look after their pre-conception health – and increase the chances of conceiving a healthy baby – include:
It's very basic: "Smoking is a big, big no-no," says Dr Davidson. It can impact on many health factors of sperm - and not in a good way.
If you're thinking about having a baby, it's a good time to look at your diet and exercise habits. "Obesity is an important factor, and losing weight can make big changes in sperm quality," Dr Davidson says.
"We want to see men get down to a normal body mass index (BMI). If men are overweight and then lose weight, we can see big improvements."
Cut down your caffeine
It's recommended that you have no more than one or two cups of coffee per day.
Slow your drinking
When it comes to alcohol, a good place to start is with the National Health and Medical Research Council's safe drinking guidelines, which suggests no more than two standard drinks on any single day. However, be aware that every beer can have an impact on sperm quality.
Sperm is produced at slightly below body temperature, so it's important to avoid overheating. This can happen in ways you may not expect.
"A classic example is truck drivers, sitting in stubbies all day, meaning the testes are not at the optimal temperature for sperm production," says Dr Davidson.
"There's good evidence that if the testes are too hot, it will impact on sperm quality. That's why they're outside the body – so they can stay cooler – and if you have them in tight underwear or sitting in tight clothes all day, that can have an effect. "
There are some good supplements on the market for men's fertility health, such as Menevit. "This contains seven vitamins and antioxidants that are thought to be good for sperm health," Dr Davidson explains.