How to get ready to be a dad

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The Fertility Society of Australia: Pre-Conception Health Special Interest Group and Your Fertility
Last updated August 2016

There is plenty of good information about how women can improve their chance of falling pregnant and having a healthy baby. But what about fathers to be? Well, research now shows that the father’s age and his health at the time of conception also affect the chance of his partner falling pregnant and the future health of the baby. Here is what you need to know about how to get ready to be a dad and give your baby the best start in life.

Age and fertility

Unlike women who are born with all the eggs they will ever have, men continue to produce sperm throughout life, which means that they can potentially reproduce into old age. But, the quality of the sperm men produce seems to decline as they get older. Partners of men who are over the age of 45 take longer to fall pregnant than partners of younger men and are more likely to have a miscarriage. And while they are rare, autism and other mental health problems are slightly more common in children with older fathers. So, if you have a partner and want to have children,
sooner is better than later.


Most people know that being obese increases the risk of health problems such as heart disease and diabetes. But many are unaware that obesity can lower a man’s fertility. This is likely due to a combination of factors including hormone problems, problems with erection and/or other health conditions linked to obesity.

Paternal obesity can also affect the health of the baby. This is because obesity influences the environment where sperm mature and this can change how the genes that are passed on to the child from the father at the time of conception function. Changes in genes in response to the environment are called epigenetic and they can affect the health of the baby at birth and in adulthood.

Men and women are twice as likely to make positive health behavior changes if their partner does too. So, a joint approach to losing weight and increasing physical activity by partners who want to have a baby will improve their chances of achieving this goal. Getting support, setting realistic goals and giving yourself enough time to achieve them, learning about nutrition and healthy eating, and exercising regularly increases your chance of losing weight and keeping it off.


Cigarette smoke contains thousands of harmful chemicals that cause damage to all parts of the body, including to sperm. Just like with obesity, smoking changes the environment where sperm mature and this can lead to socalled epigenetic changes which increase the risk of health problems in children born to fathers who smoke. Heavy smoking (>20 cigarettes per day) by fathers at the time of conception increases the child’s risk of childhood leukemia.

There is no safe limit for smoking, the only way to protect yourself and your unborn baby from harm is to quit. But, quitting can be difficult and you may need support. Speak to your doctor for advice and information about helpful resources.

Environmental toxins

As part of daily life and in some work environments we are exposed to many toxic substances and pollutants. Some of these can affect a man’s sperm and his fertility and also potentially his children’s health and development. Environmental factors that are known to have a detrimental effect on reproductive health include pesticides, heavy metals, some chemicals, harmful plastics, radiation, recreational drugs and anabolic steroids. If you and your partner plan to have a baby, talk to your doctor about how you can avoid exposure to substances that might affect your reproductive health.

Main points to remember

• If you and your partner want a baby, the sooner you start trying the better
• Being in the healthy weight range improves your chance of having a healthy baby
• If you smoke, quit and improve your and your baby’s health
• Avoid exposure to chemicals at home and at work.