30. Male Infertility: semen first, then localise

First principle: semen analysis first, then a three‑level localisation

Start with a semen analysis (standardised WHO methodology; confirm abnormal results — parameters vary biologically). Then localise:

The hormonal echo (Concept 2)

• FSH → Sertoli → spermatogenesis; LH → Leydig → testosterone.
• Primary testicular failure → high FSH (feedback lost). Central failure → low FSH/LH.

Semen vocabulary

Azoospermia — the pivotal split

Traps 🚩

• Exogenous testosterone/anabolic steroids suppress the axis (↓LH/FSH → ↓intratesticular testosterone) and impair spermatogenesis — giving testosterone to a man trying to conceive is counterproductive.
• A varicocele is common and does not automatically explain infertility — treat selectively.

Pitfalls

• Declaring infertility from a single borderline semen sample.
• Prescribing testosterone "to boost fertility."

Pearls

• 🎯 Semen first; high FSH = testicular failure; obstructive vs non‑obstructive azoospermia drives management.
• 🩺 Ask about anabolic steroid use in any man with azoospermia and small testes.

Next → The female side begins with two separate questions (Concept 31).