Why is sperm count decreasing?


Over the last 50 years, we’ve seen incredible medical breakthroughs and health improvements in many parts of the world. So it might be surprising to hear that one thing is getting steadily worse: male fertility. Average sperm count has been decreasing bit by bit every year, with no signs of stopping – but why?

Here we’ll go over some of the causes, and what you can do to break this trend.


How do we know sperm count is decreasing? 

The reality is that this decrease is not new, and it’s not the first we’re hearing about it. In 1992 the British Medical Journal published a Danish study into the decline of sperm quality between 1940 and 1990. They reported a 50% decrease in average sperm counts. This sparked not only research into how or why this was happening but also a debate into whether or not it was happening at all. 

Since the 90s, there have been more direct studies into whether or not sperm count and quality was decreasing in the average healthy man. And the results aren’t great. A large meta-study reviewing data from research all over the world found that sperm count is definitely dropping. Between 1973 and 2011, sperm counts have decreased 50-60%. That’s around 1% decrease per year.


Why is sperm count decreasing?

The question is no longer if sperm count is decreasing, but why.

Well, over the past five decades we’ve seen technology, and consumption explodes in rich and developing countries. More food, more roads, more buildings, more of everything. It’s no secret that this is causing a tonne of issues for the planet and our overall health, but people are less aware of the impact on fertility. The reality is that there are a lot of potential causes, and it’s likely the combination of factors that is damaging sperm.


Modern Lifestyle Factors


Staying still more


Far less people are taking on physical or labouring jobs and instead we see a lot more stationary jobs. There’s a lot of admin to do in the world, and on the whole it usually pays better than manual labour. But this is leading to a decline in health, and it’s not even just about the job. 

Physical exercise is great for your reproductive health. It boosts testosterone levels, gets your blood flowing, and overall has a really impressive impact on sperm parameters. You can read more in our blogs “Improving Male Fertility With Exercise” and “The Best Exercise For Male Fertility”.

And altogether this isn’t just to do with work that involves sitting at your computer. If the average person has to spend 8+ hours working 5 days a week, that can take a lot of energy. Many people have to work multiple jobs to make ends meet, so that’s even less free time. Then factor in cleaning, cooking, shopping, taking care of any kids you may have (and something vital that takes up a lot of time: sleep!) time to exercise disappears pretty quickly.

Eating more junk food


Sperm are really intricate little cells that carry human DNA, and your diet plays a big part in making those cells. Your body needs its filling of nutrients to function and produce sperm, which means lots of whole foods, grains, nuts, fruits, vegetables and fish. The issue is that many modern day diets don’t really cut it.

We can see that sperm quality has decreased mainly in the West, and that falls in line with a significant diet change in Western countries. Carbs, processed meat and vegetables, foods with high salt and sugar contents are just common staples. People are also eating more food, but still not getting enough nutrients. This is leading to a lot of health issues such as obesity, diabetes, and heart disease. But even if you’re not experiencing these conditions, your diet may be wreaking havoc on your sperm.

It’s easy to forget about what we put in our mouth. Junk food is also cheap, readily available and it tastes good. Working on your diet can take a lot of time, money and know-how that some people just don’t have. The great thing is that your diet is something you can make changes to when you recognise the issues, and your sperm quality can improve pretty quickly in response. If you’re trying to get your nutrition on the mend, read our blog: “Fertility Diet | Foods To Improve Your Fertility”.


“The typical modern lifestyle in the West is creating unnecessary stress and unbalance of  reproductive hormones, making it more difficult for males and females to have good fertility. Unless our exposure to junk food and toxic chemical contamination begins to decrease, it is unlikely that the prevalence of infertility will decrease”

Dr Fatin Willendrup, Head of Medical Affairs at ExSeed Health

Environmental factors



We use plastic pretty much every day, from the packaging for our food and clothes to the coating on our pens and books. We know that plastic is polluting nature and wildlife, but it’s also harming human health. In terms of fertility, the chemicals around plastics are the real culprit. 

Dr Shanna Swan has been monitoring the impacts of chemicals on male fertility for over 20 years. She says “[chemicals] that can interfere with or mimic the body’s sex hormones – such as testosterone and oestrogen – because these make reproduction possible. They can make the body think it has enough of a particular hormone and it doesn’t need to make any more, so production goes down.”

According to Dr Swan, a lot of these issues occur in utero. Pregnant mothers come into contact with phthalates (chemicals used to soften plastic and so are in our foods that come in plastic wrapping), and this affects the fetus. Anogenital distance (AGD) is the distance from the anus to the genitals, and is larger in males than females. In her study, Swan found that phthalate exposure correlated with boys born with shorter AGD. Males with shorter AGD are more likely to have lower sperm counts. So the impact of phthalates is just one example of chemical damages.




Air pollution is ever-present in most countries, and has a lot of detrimental effects on our health. One of the lesser known impacts is on male fertility. 

Air pollutants such as carbon dioxide, sulfur dioxide, and lead are taking a toll on male fertility. In a large META-ANALYSIS, etc etc found that the compounds in the air can disrupt the production of sperm. Compounds in the air pollution have been shown to fragment sperm DNA, change hormone levels, and decrease overall sperm motility.

These aren’t things that individuals can change. The negative impacts on fertility is just another reason to get behind sustainable development and clean energy. For yourself, you can recycle, try to avoid plastics and spend time in the countryside. 




Nowadays we don’t just want or like tech, we need it! But it isn’t the best for your balls, and may be doing a lot of damage. This is namely phones and laptops and the heat they generate.

Your testicles need to rest at a temperature around 3-5° below body heat for optimal sperm production. Testes hang out of the body in order to regulate their temperature and cool down. But this is a lot more difficult when dealing with extreme temperatures. Phones and laptops generate a lot of heat, and keeping them in your front pocket or resting on your lap for hours on end can be too much for your balls to handle. This heat and close contact can cause your testes to stop producing sperm, and kill the sperm they already have. So keep hot processors far away from your groin!

You can read our article “Testicle Temperature: How Heat Impacts Fertility” to find out more about how heat may be decreasing your sperm quality, and how to avoid it.


What can you do to counteract this trend?


You can do a lot to help out your own sperm. Once you know these everyday things come with a big risk to future fertility, taking steps to avoid some of them isn’t too difficult. You can’t really avoid the environmental impacts on sperm, but you can still improve it in other ways.

The simplest solution? Living healthily. Regular exercise, a healthy diet rich in nutrients, keeping your groin safe from injury and excessive heat. 

You can also keep an eye on your sperm health with an ExSeed home-test kit. The overall decrease in sperm health doesn’t mean every guy’s health is slightly worse than it would’ve been 10 years ago. Some men will have much, much lower sperm parameters. Currently, 1 in 6 heterosexual couples struggle to get pregnant, and around 30-50% of fertility issues are due to male factor infertility. So if you’re looking to have kids now or in the future, the best thing you can do is get your swimmers checked out.

Not only can you test your sperm from home, the free ExSeed app gives you detailed information about your sperm quality and what you can do to improve it. You can access support and advice from specialists to find out what options are available to you and what changes you can make.


Want to know more about protecting our sperm health? Join our FREE webinar on the 3rd November – grab your tickets here. 

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