Male Factor Infertility Beyond the Semen Analysis

When a fertility work-up focuses on the female partner, the male side is often reduced to a single test: the standard semen analysis. That test is useful, but it is a headcount — not a full assessment of sperm health.

What the standard analysis measures

A conventional semen analysis reports three things: count (how many), motility (how well they move), and morphology (how they are shaped). A result within the reference ranges is reassuring on those three measures — and nothing else.

What it misses

Two factors that strongly influence fertility sit entirely outside the standard test:

• Sperm DNA fragmentation — breaks and damage in the genetic material the sperm carries. Sperm can look normal under a microscope yet carry significant DNA damage that affects fertilisation, embryo quality, and miscarriage risk.
• The sperm microbiome — the microbial environment of the male reproductive tract, which can drive inflammation and oxidative stress affecting sperm quality.

Because these are not part of a routine analysis, a man can be told everything is "normal" while the actual limiting factor goes undetected.

Why this reframes 'unexplained' cases

A meaningful share of cases labelled unexplained involve male factors that the standard test was never designed to catch. Extending the investigation on the male side — to DNA fragmentation and the sperm microbiome — can turn an "unexplained" case into an explained, and often addressable, one.

This article is educational and does not replace individualised medical advice. A practitioner can advise whether extended male-factor testing is appropriate in your situation.