Poor sperm quality often has no visible signs or symptoms. A man can feel healthy, ejaculate normally and have semen that looks typical while still having a low sperm count, reduced sperm movement or other abnormalities.
The clearest way to assess sperm quality is a semen analysis. Changes in semen, pain or difficulty conceiving can be reasons to seek advice, but they cannot diagnose unhealthy sperm on their own.
What does “unhealthy sperm” mean?
“Unhealthy sperm” is an everyday phrase rather than a specific diagnosis. It usually refers to problems with one or more sperm characteristics:
- Count or concentration: fewer sperm than expected.
- Motility: a lower proportion of sperm moving, particularly forwards.
- Morphology: a lower proportion meeting the laboratory’s criteria for normal shape.
- Vitality: a lower proportion of sperm that are alive.
A semen analysis measures these characteristics alongside properties of the fluid containing the sperm. Cleveland Clinic’s semen-analysis guide explains what the examination includes.
An abnormal result does not automatically mean infertility. Equally, a result within the reference range cannot guarantee pregnancy.
1. Difficulty getting a partner pregnant
Difficulty conceiving is often the first reason a man discovers a sperm problem. There may be no other symptoms.
However, a delay in pregnancy cannot identify which partner has a fertility issue. Both partners may need assessment.
The NHS recommends seeing a GP after a year of regular unprotected sex without pregnancy, or after six months if your partner is 36 or older. Seek advice sooner if there is a known fertility concern.
Our guide to how to tell if a man is fertile or infertile explains why testing is more useful than relying on outward signs.
2. Persistently low semen volume
A consistently small amount of semen is worth discussing with a healthcare professional, especially if it represents a change.
Semen volume and sperm count are different measurements. A small ejaculate does not necessarily mean a low sperm concentration, while a large ejaculate does not prove that sperm quality is good.
Collection also matters. Losing part of a sample can affect the result, so tell the laboratory if that happens.
3. A lasting change in semen consistency
Semen normally changes consistency after ejaculation. It may initially look gel-like before becoming more liquid.
Persistently unusual consistency can justify assessment, but thick or watery semen alone cannot tell you whether sperm count or movement is normal.
Cleveland Clinic lists liquefaction among the characteristics assessed during testing. Our article on what healthy semen looks like explains normal texture changes and findings worth investigating.
4. New or persistent discolouration
Semen is usually white-grey, according to Mayo Clinic. Colour can change temporarily, and a change does not automatically indicate poor sperm quality.
Persistent discolouration, particularly when accompanied by pain or other symptoms, deserves medical advice.
Colour describes the seminal fluid. It does not measure the sperm cells within it.
For more detail, read what colour healthy semen should be.
5. Blood in semen
Pink, red or brown semen may contain blood.
The NHS advises seeing a GP for blood in semen. It often has a harmless cause and clears without treatment, but it should still be checked.
Blood in semen is a symptom to investigate, rather than proof of infertility or unhealthy sperm.
6. Testicular pain, swelling or a lump
Changes in the testicles need medical assessment. They may reflect a condition affecting reproductive health, but they do not establish sperm quality.
Go to A&E immediately or call 999 if you have sudden, severe testicular pain. The NHS guidance on testicle pain also advises an urgent GP appointment or help from NHS 111 for a lump, swelling or changes in how a testicle feels.
Do not wait for a sperm test before seeking help for these symptoms.
What if there are no symptoms?
Having no symptoms does not rule out a sperm problem.
Normal ejaculation, a strong sex drive and typical-looking semen cannot establish sperm count, motility or morphology. A previous pregnancy also does not guarantee that current sperm quality is unchanged.
Our article on whether you can tell if sperm are healthy by looking explains the limits of visual checks.
How do you find out whether sperm quality is poor?
A semen analysis is the usual starting point. The AUA/ASRM male infertility guideline recommends assessing semen results alongside reproductive history.
Individual measurements cannot reliably determine fertility on their own. Several significant abnormalities together are more concerning than one isolated finding.
Results also vary between samples. NICE guidance recommends a repeat confirmatory test when the first semen analysis is abnormal. Repeat testing is ideally performed around three months later. If no sperm or a severely reduced sperm concentration is found, confirmation should take place sooner.
Home sperm tests vary in what they measure. Check whether a test reports concentration, motility or other characteristics. Seek clinical advice if you have symptoms or ongoing difficulty conceiving, even if a home test gives a reassuring result.
Our guide to male fertility tests compares the options and their limitations.
Frequently asked questions
Can unhealthy sperm look normal?
Yes. Semen appearance cannot reliably reveal sperm count, movement or shape. Testing is needed.
Does watery semen mean a low sperm count?
Not necessarily. Appearance alone cannot establish concentration. A persistent change may justify assessment.
Does thick semen mean healthy sperm?
No. Thickness is a characteristic of the fluid, not a reliable measure of sperm quality.
Can I have poor sperm quality even if I have a high sex drive?
Yes. Sex drive does not measure sperm count or motility.
Does an abnormal semen analysis mean I cannot have children?
No. Results need clinical interpretation, and some abnormalities require repeat testing or further investigation. A semen analysis is one part of a fertility assessment.
