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There are many factors that affect a man’s sperm count and sperm quality, including lifestyle factors such as alcohol and drug consumption, and whether you’re a healthy weight. Environmental factors also play a role, including chemicals you might be exposed to at work or in your home.  

The hormone testosterone is crucial for sperm production, and some drugs such as anabolic steroids can harm your sperm count and quality for a long period of time. Anabolic steroids are synthetic drugs that mimic testosterone. Some people misuse them to build muscle or enhance sporting performance despite a range of health risks.  

The good news is, there are many things you can do to protect your sperm from damage and improve it if you want to conceive and have a healthy baby in future.  

It takes about three months to make new sperm, so it’s worth making changes that can improve your fertility at least three months before trying to conceive. This can help prevent fertility problems and the need for fertility treatments, which are costly and invasive. It can also increase your chance of a healthy child.  

About one in 20 Australian men are diagnosed as sub-fertile (meaning they don’t conceive easily) or infertile (unable to conceive despite frequent sex for a year or more). And about one in six heterosexual couples experience infertility. In half of all these cases, a male problem is identified. The most common problem for a man is a low sperm count or sperm that doesn’t work the way it’s meant to.  


GP visit

What factors affect sperm count? 

Your sperm count and the quality of your sperm can be measured by a semen analysis. This involves freshly ejaculated semen being examined under a microscope in a laboratory.   

A semen analysis will report on the total number of sperm found in the sample and the sperm count or sperm concentration (the number of sperm per millilitre of semen). The analysis will also look at the quality of sperm, which is discussed in more detail below. 

Factors that can lower your sperm count, include:  


semen analysis


What is quality sperm? 

Your sperm count is important, but so too is the quality of your sperm. During a semen analysis, a scientist will report on how many sperm are moving well (motility) and how many are ideally shaped for fertilising an egg to make a baby (morphology).  

Along with these measures, the scientist will also measure:  

  • whether your volume of semen is in a normal range  

  • if there’s white blood cells present, signalling an infection 

  • the pH of your semen (if it’s more acidic than it should be) 

  • if sperm antibodies are present (a protein that can fight sperm).  


Low quality sperm can make it very hard and sometimes impossible to get pregnant. About two thirds of men who struggle to conceive have low sperm count and/ or low quality sperm. 


Factors that can affect the quality of your sperm include:  

  • Being overweight. It can affect sperm movement and increase abnormal sperm. 

  • Smoking cigarettes. Research shows the more cigarettes you smoke, the worse your sperm quality is. 

  • Heat. Your testes need to be a few degrees cooler than the rest of the body to make good quality sperm. 


Healthy eating


What you can do 

There’s a lot you can do to protect your sperm and improve it.Preconception health checklist for men
Here’s a list of practical steps from our pre-conception checklist for men wanting
to increase their chance of conceiving a healthy baby.   

Aim to:   

  • eat a healthy, balanced diet  

  • exercise regularly   

  • maintain a healthy weight 

  • quit smoking, recreational drugs and heavy drinking 

  • avoid anabolic steroids 

  • visit your GP for a pre-conception health check to test for STIs and discuss any medicines you’re taking.  


And remember to protect your testes by: 

  • avoiding regular hot baths or spas 

  • keeping your computer and phone away from your lap 

  • wearing protective gear when playing sport. 


Aside from potentially boosting your fertility, making these changes could also influence your future child’s health.  

Research is beginning to show that sperm DNA can be altered by different lifestyle factors such as smoking or being overweight, which can change how genes work. This is called ‘epigenetics’. Since this DNA is passed on to your child, it can affect how your child’s own DNA and genes work. While research is still in its early stages, it does suggest that doing what you can to protect your sperm will help give your child the best start to life.  


Your Fertility articles

Other Your Fertility articles on this topic 

Fertility Week: Healthy sperm, healthy baby

Men in the healthy weight range have healthier sperm 

Wearing boxer shorts might improve your sperm 

Declining sperm counts and how the trend can be reversed