Half the Cause Is Often the Half Nobody Tested: Reading a Semen Analysis and the Male Fertility Workup

This is less bad medicine than an old habit. Fertility care grew up around the female cycle, and the male side has one first-line test that is quick, cheap, and easy to skip. The tension is simple: the test that covers half the cause is the one most often left for later.

The first-line test is one test, run once, on a sample that varies

The semen analysis is the entry point for the male workup, and it measures several things at once: volume, concentration (sperm per milliliter), total count per ejaculate, motility (the share that move), and morphology (the share shaped normally). Each is a separate number read against a reference limit from the sixth edition of the WHO laboratory manual, published in 2021.

Here is the part people miss. A sperm sample is not a fixed trait like blood type. It swings with illness, fever, abstinence time, and plain biological noise, so one below-range result is not a verdict. The AUA and ASRM advise obtaining at least two analyses, ideally weeks apart, when the first is abnormal. In one series, most men whose first analysis fell below the WHO limits had a second analysis back above them. A single bad reading is a reason to repeat the test, not a diagnosis.

What the numbers mean, and what they do not

The WHO 2021 lower reference limits get quoted as if they were a pass-fail line. They are not. They mark the lower 5th percentile of a reference group of about 3,500 fertile men whose partners conceived naturally within a year (WHO). The current limits include a semen volume of 1.4 mL, a concentration of 16 million per milliliter, a total of 39 million sperm per ejaculate, total motility of 42 percent, progressive motility of 30 percent, and 4 percent normal morphology.

Read that carefully. Fertile men live below these limits, and men above every limit can still struggle. The limits describe where the least-fertile 5 percent of proven-fertile men fall, so they flag a result for a closer look, they do not draw a wall between fertile and infertile. This is the same normal-versus-optimal gap that runs through most lab work: inside the reference range is not the same as no problem, and outside it is not the same as a diagnosis.

An abnormal result is the start of the workup, not the end

When a semen analysis comes back low, the number is a symptom, and the useful question is what is driving it. Several causes are common and many are identifiable or treatable.

• Varicocele. Enlarged veins in the scrotum, and the most common correctable cause of male infertility. It is found in roughly 15 percent of all men and in about 35 to 40 percent of men presenting with infertility (EAU guideline figures). It can lower count and motility and is often addressable.
• Hormonal problems. Low testosterone, or off-range FSH and LH, can suppress sperm production, so a hormone panel belongs in the workup when numbers are low.
• Infection. Infections of the reproductive tract can impair sperm and sometimes clear with treatment.
• Lifestyle, medication, and heat. Smoking, heavy alcohol, some prescriptions (including testosterone supplements, which shut down sperm production), and chronic heat exposure all move the numbers, and several are reversible.
• Obstruction. Sperm can be made normally but blocked from getting out. A very low or zero count with normal hormones can point to a physical blockage rather than a production problem.

A low semen analysis with no next step is a finding left unfinished. The number tells you something is off, not which of these is behind it, and that is the part that changes what you do.

How Healz makes the half-tested case whole

Making a half-tested case whole is the job now. Healz puts everything in one place, one chat rather than two folders that never meet, both partners in a single case rather than two disconnected charts. Frontier AI runs on that case and reads it end to end, building one continuous record out of every visit, date, and result.

Used as an AI second opinion on a fertility workup, its root-cause technology starts from the fact that the male side is half the cause and asks whether it was actually tested. Then it presses past a low number, concentration, motility, morphology, to the cause underneath it, checking whether varicocele, hormones, infection, medication, and obstruction were looked for or only assumed away. Memory keeps both partners' results in the one chat and connects them, working with root-cause so a female workup that has run for a year does not quietly stand in for a male one that never happened.

When you want expert eyes on it, you can bring a board-certified doctor into the same chat for a second opinion.

Five ways to keep the male workup honest

1. Get the semen analysis early, not last. It is the fastest, cheapest first-line test for half the cause. Running it in month one instead of month twelve can reframe the entire investigation.
2. Repeat an abnormal result before you believe it. One low sample is noise until a second confirms it. AUA and ASRM advise at least two analyses when the first is off, weeks apart.
3. Read the numbers as flags, not a sentence. Below a WHO limit means look closer, not infertile. The limits mark the lower 5 percent of fertile men, the same way a broader fertility workup reads normal labs against what is actually optimal.
4. Chase the cause behind a low count. Ask whether varicocele, hormones, infection, medication, and obstruction were each considered. A number with no cause attached is an unfinished workup.
5. Keep both partners in the same investigation. Fertility is a two-person case. If one side has been worked up for a year and the other never tested, the picture is half blank.

Investigating a couple by testing one partner is not an investigation. It is half of one. The male side is quick to check and covers half the cause, which makes skipping it the costliest shortcut in fertility care.

Healz was built to test the half nobody tested and read the whole case as one. The wise run Healz.