Male Infertility: 5 Important Tests Most Men Are Never Offered
If you've been told that male factor infertility is the main reason you're struggling to conceive, it can feel incredibly frustrating. Especially when you're otherwise young, healthy, and expected pregnancy to happen quickly.
The good news is that sperm health is often more modifiable than people realise.
As a fertility dietitian, I regularly work with couples who have spent months trying to conceive, only to discover that issues with sperm count, sperm motility, sperm morphology, or sperm DNA fragmentation may be reducing their chances of pregnancy.
Many men are told they have "poor sperm quality" but are never given a clear explanation as to why. Others are reassured that their results are only slightly below normal and advised to keep trying.
The reality is that conception requires both a healthy egg and a healthy sperm. Even when female fertility appears optimal, sperm quality can influence fertilisation, embryo development, implantation, and ultimately whether a pregnancy progresses successfully.
Understanding what is driving male infertility is often the first step towards improving fertility outcomes and bringing you closer to the family you're trying to build.
1. Inadequate Nutritional Testing
Many men are advised to "take a men's fertility supplement" without anyone actually assessing whether they have nutrient deficiencies.
Sperm production is one of the most metabolically demanding processes in the body. Every sperm cell requires DNA replication, mitochondrial energy production, antioxidant protection, and membrane development.
Deficiencies or insufficiencies in key nutrients can negatively impact sperm count, motility, morphology, and DNA integrity. Optimal levels of nutrients are very different to “normal” levels when investigating male factor infertility.
Some of the nutritional markers I commonly assess include:
- Vitamin B12
- Folate
- Homocysteine
- Omega-6:3 ratio (ZinZino Balance Test)
- Vitamin D
- Zinc
- Selenium
- Thyroid function
- Markers of insulin resistance and metabolic health
Two of the most overlooked markers are homocysteine and omega-6:3 ratio.
Elevated homocysteine may indicate impaired methylation, increased oxidative stress, and reduced DNA integrity. Research has linked elevated homocysteine with poorer sperm quality and impaired spermatogenesis (sperm production).
Your omega-6:3 ratio is a reflection of cellular health: it tells us whether sperm are being built from the right raw materials and whether they are operating in an environment that supports optimal fertility. We are aiming for an omega-6:3 ratio of less than 3:1 and making sure your red blood cells are replete with both omega-3 fatty acids - EPA and DHA. DHA is a major structural component of sperm membranes and is essential for membrane fluidity, sperm maturation, motility, and the ability of sperm to fertilise an egg.
An unbalanced omega-6:3 ratio is linked to higher body inflammation and oxidative stress, both of which can damage sperm membranes and DNA, leading to poorer sperm count, motility, morphology, and increased DNA fragmentation.
Rather than guessing which supplements may help - spoiler alert, most omega-3 supplements are already oxidised - testing allows us to identify the specific nutritional barriers affecting sperm production.
2. Sperm DNA Fragmentation Testing
A standard semen analysis tells us about:
- Count
- Motility
- Morphology
What it does not tell us is whether the DNA carried inside the sperm is intact.
A man can have completely "normal" semen parameters yet still have high levels of sperm DNA fragmentation (broken pieces).
Elevated DNA fragmentation has been associated with:
- Reduced natural conception rates
- Recurrent miscarriage
- Poor embryo development
- Lower IVF success rates
- Increased risk of failed implantation
Factors that may contribute to DNA fragmentation include:
- Oxidative stress (causes damage like rust)
- Smoking
- Varicocele
- Infection
- Obesity
- Environmental toxin exposure like endocrine disrupting chemicals
- Nutrient deficiencies
- Advanced paternal age
In couples experiencing recurrent pregnancy loss, unexplained infertility, repeated IVF failure, or poor embryo quality, sperm DNA fragmentation testing can provide valuable information that a standard semen analysis simply cannot.
3. The Seminal Microbiome
One of the most exciting areas of fertility research is the seminal microbiome.
Just as we now understand the importance of the gut microbiome, uterine & vaginal microbiome, researchers are discovering that the semen microbiome also influences reproductive outcomes.
An imbalance in the seminal microbiome has been associated with:
- Reduced sperm concentration
- Poor motility
- Increased oxidative stress
- Increased inflammation
- Higher levels of sperm DNA damage
Certain bacterial species appear to be associated with poorer fertility outcomes, while others may support a healthier reproductive environment.
The challenge is that this testing is rarely offered routinely.
For men with unexplained infertility, recurrent miscarriage, poor embryo quality, elevated DNA fragmentation, or persistently abnormal semen parameters, investigating the seminal microbiome may reveal an underlying contributor that would otherwise remain undetected.
Tests such as ScreenMe UK and FERTILYSIS Male Microbiome Testing can help uncover microbial imbalances that may contribute to inflammation, oxidative stress, sperm DNA damage, and impaired fertility outcomes. I use both of these tests in the clinic.
4. Oxidative Stress: The Hidden Driver of Sperm Damage
Sperm cells are particularly vulnerable to oxidative stress.
In fact, oxidative stress is believed to contribute to a significant proportion of male infertility cases.
Excessive reactive oxygen species (ROS) can damage:
- Sperm membranes
- Mitochondria
- DNA
- Cellular energy production
This damage can impair fertilisation potential even when traditional semen parameters appear acceptable.
Common contributors include:
- Smoking
- Alcohol excess
- Obesity
- Poor sleep
- Chronic inflammation
- Nutrient deficiencies
- Environmental toxins
- Infections
Addressing oxidative stress is one of the key reasons why targeted nutrition, lifestyle changes, and appropriate supplementation can dramatically improve sperm health over a 3–4 month period.
5. Looking Beyond "Normal"
One of the biggest misconceptions I encounter is the belief that "normal" semen results mean fertility is optimal.
The reference ranges used in semen analysis are based on the lower fifth percentile of fertile men. To achieve pregnancy quickly, we should be aiming for semen parameters to be on the 50th percentile.
In other words, "normal" does not necessarily mean optimal.
A man may sit within the reference range and still have sperm quality that could be improved.
This is why I look at the whole picture:
- Nutritional status
- Metabolic health
- DNA integrity
- Oxidative stress
- Seminal microbiome
- Lifestyle factors
- Environmental exposures
For me, the goal is not simply to be normal.
The goal is to create the healthiest sperm possible. And this is especially important if we are dealing with advanced maternal age as the repair capacity of the egg is reduced as the woman gets older.
So we need top-notch sperm!
The Bottom Line
Sperm takes approximately 72–80 days to develop.
That means the sperm involved in conception three months from now are being influenced by today's diet, lifestyle, nutrient status, inflammation levels, and environmental exposures.
If male factor infertility has been identified—or if conception simply isn't happening despite "normal" semen results—there may be important investigations that have not yet been performed.
The men who achieve the greatest improvements in sperm health are rarely the ones who take random supplements.
They are the ones who identify the underlying drivers affecting sperm production and address them with a targeted, evidence-based approach.
Because when it comes to fertility, sperm quality matters just as much as egg quality.
Wondering what's affecting your sperm health? Book a free strategy call to uncover the underlying causes and create a personalised fertility plan.
Otherwise, feel free to email me at [email protected] - I love answering questions!
