Getting your semen analysis results back can feel overwhelming—especially when the numbers don’t mean much without context. A normal sperm count starts at 16 million sperm per milliliter (ml) of semen, according to the World Health Organization (WHO) 6th edition laboratory manual, published in 2021. Anything below 15 million per ml is classified as low.
That said, sperm count alone doesn’t tell the whole story. A semen analysis measures several parameters at once. Understanding each one helps you—and your doctor—build a clearer picture of your fertility.
What Does a Semen Analysis Actually Measure?
A semen analysis (also called a sperm count test or male fertility test) evaluates both the quantity and quality of your sperm. It looks at the following:
- Volume: How much semen you produce in a single ejaculation
- Sperm concentration: The number of sperm per milliliter of semen
- Total sperm count: The total number of sperm across the entire sample
- Motility: The percentage of sperm that move efficiently
- Morphology: The percentage of sperm with a normal shape
- pH: The acidity of the semen
- Liquefaction time: How quickly semen changes from a thick gel to a fluid
Abnormal results in any of these areas can affect fertility.
What Are the Normal Reference Ranges for Semen Parameters?
The table below reflects the lower reference limits from the WHO 2021 6th edition—the most current global standard. These values represent the 5th percentile of fertile men, meaning results at or above these numbers fall within the normal range.
| Parameter | Lower Reference Limit (WHO 2021) |
| Semen volume | 1.4 ml |
| Total sperm number | 39 million per ejaculate |
| Sperm concentration | 16 million per ml |
| Progressive motility | 30% |
| Total motility | 42% |
| Normal morphology | 4% |
| Sperm vitality (live) | 54% |
| pH | ≥7.2 |
A few things worth noting. The morphology threshold—just 4%—surprises many people. Most sperm are structurally imperfect. As long as at least 4% have a normal shape, that falls within the acceptable range.
It’s also worth knowing that sperm count naturally varies from day to day. A single abnormal result doesn’t confirm infertility. The European Association of Urology (EAU) recommends repeating a semen analysis if results are abnormal, ideally within two to three weeks.
What Does It Mean If Your Sperm Count Is Low?
A sperm concentration below 15 million per ml is classified as oligospermia (ol-ih-go-SPER-me-uh)—the medical term for a low sperm count. There are degrees of severity:
- Mild oligospermia: 10–15 million sperm per ml
- Moderate oligospermia: 5–10 million sperm per ml
- Severe oligospermia: fewer than 5 million sperm per ml
A separate condition called azoospermia (ay-zoh-uh-SPER-me-uh) means no sperm are present in the semen at all.
A low sperm count reduces the odds of a sperm reaching and fertilizing an egg, but it doesn’t make pregnancy impossible. Many people with oligospermia go on to conceive, either naturally or with assisted reproductive techniques such as in vitro fertilization (IVF).
What Can Cause a Low Sperm Count?
There are several possible causes. Some are medical, others are lifestyle-related.
Medical and Physical Causes
- Varicocele: Swollen veins in the scrotum are the most common cause. According to research published in Fertility and Sterility, about 4 in 10 males with low sperm counts have a varicocele. Surgery can often improve sperm count in these cases.
- Hormonal imbalances: The hypothalamus and pituitary gland regulate the hormones needed to produce sperm. Disruptions to these systems can lower sperm production.
- Infections: Sexually transmitted infections (STIs) like gonorrhea and HIV, as well as other bacterial or viral infections, can damage sperm-producing tissue.
- Genetic conditions: Klinefelter syndrome and cystic fibrosis are examples of inherited conditions that can affect sperm production.
- Blockages: Scar tissue from past infections or surgery can block the tubes that carry sperm.
Lifestyle and Environmental Causes
Several factors within your control can lower your sperm count, according to the Cleveland Clinic and Mayo Clinic:
- Smoking tobacco
- Heavy alcohol use
- Recreational drugs, including marijuana and cocaine
- Obesity or a BMI above 25
- Prolonged stress
- Exposure to heat (e.g., frequent use of hot tubs or saunas)
- Exposure to industrial chemicals, pesticides, or heavy metals like lead and mercury
Certain prescription medications can also reduce sperm production. If you’re concerned about a medication, speak with Docto Nudell before stopping it.
When Should You See a Doctor About Your Results?
See a healthcare provider if:
- You and your partner have been trying to conceive for 12 months without success (or 6 months if your partner is over 35)
- You experience pain, swelling, or a lump in the testicle area
- You have a history of reproductive system surgery, infections, or hormone issues
- Your semen analysis returns results below the WHO reference limits
Abnormal results are a signal to investigate further—not a final verdict. Your doctor may order hormone blood tests, genetic testing, or a scrotal ultrasound to identify the underlying cause.
Can You Improve a Low Sperm Count?
It depends on the cause. For many men, lifestyle changes can make a measurable difference. Evidence-based steps include:
- Quitting smoking: Smokers tend to have lower sperm counts than non-smokers (Mayo Clinic, 2024)
- Reducing alcohol intake: Heavy alcohol use lowers testosterone and impairs sperm production
- Maintaining a healthy weight: Obesity can directly alter sperm quality and hormone levels
- Managing stress: Chronic stress is linked to reduced semen quality
- Avoiding heat exposure: Keep your laptop off your lap and limit time in hot tubs
For medical causes like varicocele or hormonal imbalances, treatment can often improve sperm count significantly.
What to Do After Getting Your Results
Getting a semen analysis done is the right first step. If your results fall outside the normal ranges, don’t treat it as a definitive diagnosis. Sperm parameters fluctuate, causes are often treatable, and fertility medicine has advanced considerably.
Talk to a urologist or reproductive endocrinologist who can review your full results in context. Whether the next step is a lifestyle change, medical treatment, or exploring assisted reproduction, there are clear paths forward.