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What’s in a Semen Analysis? Understanding the Numbers That Matter in Male Fertility
- Eric Lacy, PhD
- Jun 5
- 3 min read
Updated: Aug 12
When people think about fertility, they often focus on ovulation, hormones, or egg quality. But male fertility plays an equal role in conception—and one of the most foundational tools we have to assess it is the semen analysis.
Simple in name, but rich in data, a semen analysis offers a window into male reproductive health. Whether you're a patient, a provider, or building technology in this space, understanding what those numbers mean can help guide smarter conversations and more effective care.
Here’s a breakdown of what’s tested—and why it matters.
1. Volume – How much is there?
What it is: The total amount of semen ejaculated, measured in milliliters (mL).
Why it matters: Low volume (<1.5 mL) may suggest issues with the seminal vesicles, blockages, or even retrograde ejaculation. Too little volume can limit how many sperm make it into the reproductive tract.
✅ Normal range: 1.5–6.0 mL
🔍 Low result may indicate: Obstruction, ejaculatory duct issues, or collection error.
2. Concentration – How many sperm are in each milliliter?
What it is: The number of sperm per milliliter of semen.
Why it matters: Sperm count affects the probability of one reaching and fertilizing an egg. Lower counts reduce the chances, especially without assisted reproductive technology (ART).
✅ Normal range: ≥15 million sperm/mL
🔍 Low result may indicate: Testicular dysfunction, hormonal imbalance, or lifestyle factors (heat, toxins, etc.).
3. Motility – How well are they moving?
What it is: The percentage of sperm that are actively moving—and how they move.
Why it matters: Movement is essential for sperm to reach and penetrate the egg. Total motility includes both progressive (forward-moving) and non-progressive motion.
✅ Normal range: ≥40% motile (with ≥32% progressively motile)
🔍 Low result may indicate: Structural sperm defects, oxidative stress, or past infections.
4. Morphology – What do they look like?
What it is: The percentage of sperm with a normal shape (head, midpiece, tail).
Why it matters: Abnormally shaped sperm may not be able to fertilize an egg. However, morphology is complex—strict criteria (Kruger method) mean even healthy men can have low percentages.
✅ Normal range: ≥4% normal forms (Kruger criteria)
🔍 Low result may indicate: Genetic issues, heat exposure, varicocele, or toxins.
5. Vitality – Are they alive?
What it is: The percentage of live sperm in a sample (tested when motility is low).
Why it matters: Distinguishing between dead/non-motile and alive/non-motile sperm is critical for diagnosing underlying issues.
✅ Normal range: ≥58% live sperm
🔍 Low result may indicate: Cell damage, oxidative stress, or infection.
What Do Abnormal Results Mean?
An abnormal result doesn’t automatically mean infertility. In fact, many people with suboptimal semen parameters can still conceive—especially with the help of ART or lifestyle changes.
But abnormal values can be a signal worth exploring:
Low count or motility might suggest hormonal or testicular dysfunction
Poor morphology could point to oxidative stress or environmental exposure
Low volume could mean retrograde ejaculation or ductal obstruction
In some cases, these findings lead to further testing—such as hormone panels, genetic screening, or scrotal ultrasound.
Male Fertility Deserves Equal Attention
Too often, the fertility conversation centers around one partner. But sperm health is half the equation.
The semen analysis remains a cornerstone diagnostic—and a gateway to understanding and improving reproductive potential. If you’re trying to conceive or working with patients who are, make sure male fertility isn’t an afterthought.
Bottom line: The semen analysis is more than just a test—it’s a starting point. A place to understand what’s working, what’s not, and what’s possible.
Want to Learn More?
Here are a few trusted resources that dig deeper into semen parameters and male reproductive health:
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