Male factor is involved in roughly half of all infertility cases, either as the primary issue or as a contributor alongside female factors. Yet the workup for a couple struggling to conceive still often starts and ends with the woman, and men frequently discover their role only after months or years of investigation.
Sperm health is also changing. Multiple large meta-analyses have documented a decline in average sperm concentration over the past several decades, and while the causes remain debated, the trend is real.
What a semen analysis tells you, and does not
The first test in a male fertility workup is a semen analysis. It measures several parameters against reference values published by the World Health Organization, updated most recently in 2021. The main ones:
- Concentration, sperm per milliliter
- Total motile count, the total number of moving sperm in the sample
- Morphology, the percentage with normal shape
- Volume, pH, and viscosity of the ejaculate
A single normal analysis does not rule out male infertility, and a single abnormal one does not confirm it. Sperm production takes about seventy-four days, and stress, illness, or a fever within the prior three months can affect results. At least two analyses spaced several weeks apart, ideally with two to five days of abstinence before each, are the standard.
What the semen analysis does not measure is sperm DNA fragmentation, which some clinics offer as an add-on. The evidence supporting DNA fragmentation testing for guiding treatment is still evolving, and the AUA and ASRM currently recommend it selectively rather than routinely.
Why sperm counts may be falling
The drivers are not fully understood, but the leading candidates include:
- Obesity and metabolic disease, which affect hormone signaling and testicular temperature
- Endocrine-disrupting chemicals in plastics, pesticides, and industrial exposures
- Heat exposure, from laptops on laps, prolonged sauna use, or occupations with heat stress
- Anabolic steroid use, which suppresses natural sperm production, sometimes long-term
- Cannabis and heavy alcohol use, both associated with reduced parameters
- Certain medications, including testosterone therapy, finasteride, some antibiotics, and chemotherapy agents
Age matters more than the older cultural narrative allowed. Paternal age over forty is associated with longer time to conception, higher miscarriage rates, and a modest increase in certain conditions in offspring. Fertility does not have a hard cutoff for men, but it is not indifferent to time.
The workup beyond the analysis
An abnormal semen analysis warrants a broader look. A reproductive urologist will typically evaluate:
- Hormonal profile, including testosterone, LH, FSH, prolactin, and estradiol
- Physical exam, particularly looking for a varicocele, an enlarged vein around the testicle that is a common and often treatable cause of male infertility
- Scrotal ultrasound where indicated
- Genetic testing, including karyotype and Y-chromosome microdeletions, for men with severely low counts
Some of the most common causes are correctable. Varicocele repair can improve parameters in appropriately selected men. Stopping exogenous testosterone or anabolic steroids and starting recovery protocols with hCG or clomiphene can restore production, though not always fully.
If you are on testosterone therapy and want biological children, the priority is banking sperm before or during a treatment pause, not assuming production will return on its own.
What men can actually do
The lifestyle interventions supported by evidence are unglamorous but real:
- Achieve and maintain a healthy weight
- Avoid tobacco, limit alcohol, and reconsider cannabis if trying to conceive
- Reduce heat exposure to the testicles during the months of attempted conception
- Address sleep and treat sleep apnea
- Consider a multivitamin with antioxidants, though the evidence for specific supplements is modest
Bank sperm before chemotherapy, radiation, or gender-affirming hormones, and consider banking before starting testosterone therapy if fertility may matter later.
The bottom line
Male fertility is half of the equation, and it responds to a real workup and to lifestyle changes made early enough to matter. If conception has been difficult for six to twelve months, both partners deserve evaluation, and the male workup is faster and less invasive than most men expect.