The Proof with Simon Hill
The Proof with Simon Hill

The Fertility Test Most Men Are Never Offered | Dr Michael Eisenberg and Dr Natalie Crawford

August 10, 2026

AI Summary

5 min read

The Fertility Test Most Men Are Never Offered

Most men have no idea how their sperm is doing — and that matters far beyond whether they can get a child. A semen analysis can predict not just fertility but also future risk of chronic disease, metabolic problems, and even earlier death. Yet the current medical system routinely skips testing the male partner, sometimes for years, while the female partner undergoes invasive treatments. This conversation between urologist Dr. Michael Eisenberg and reproductive endocrinologist Dr. Natalie Crawford, hosted by Simon Hill, makes the case that male fertility is a neglected but powerfully actionable health signal.

Why the System Fails Men

According to Crawford, infertility is caused by a male factor about half the time — one third solely male, one third a contribution from both partners. But the standard approach is backward. Most couples are told to "just try for a year" before any testing begins, and even then, the female partner is often evaluated and treated first. Crawford sees couples who have done intrauterine insemination without ever having a semen analysis. Eisenberg estimates that a quarter to a third of infertile men are never evaluated at all.

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What you'll learn

  • 1 (00:04) **Why This Conversation Exists** - Simon explains his personal motivation for creating the episode after learning about sperm's impact on conception, pregnancy, and long-term male health.
  • 2 (01:31) **Introducing the Experts** - Dr. Michael Eisenberg (Stanford urologist) and Dr. Natalie Crawford (reproductive endocrinologist) describe their clinical focus on male fertility.
  • 3 (05:45) **The Current System Fails Patients** - The doctors critique the standard guideline of waiting a year before testing, which often delays crucial male evaluation.
  • 4 (13:41) **Why the Guidelines Are Outdated** - The current "fail first" model for infertility diagnosis is criticized, with a call for proactive testing for both partners.
  • 5 (16:12) **What a Semen Analysis Actually Tells You** - Ejaculation volume is not a proxy for sperm health; a lab test is required to assess concentration, motility, shape, and DNA damage.
  • 6 (22:39) **The Cannabis & Sperm Problem** - Cannabis use, especially daily, is a common and underappreciated contributor to poor sperm function and IVF failure.
  • 7 (25:15) **The Sperm Check Engine Light** - Sperm health is a powerful biomarker for a man's current and future overall health, even if he doesn't plan to have children.

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Show Notes

About one in seven couples are unable to conceive after a year of trying, and roughly half of those cases involve a male contribution. Yet in a quarter to a third of them, the man is never properly evaluated. In this episode I sit down with Dr Michael Eisenberg, a urologist and Director of Male Reproductive Health at Stanford University, and Dr Natalie Crawford, a reproductive endocrinologist and co-founder of Fora Fertility in Austin, Texas.

This is the comprehensive male fertility resource I went looking for and couldn't find, and I have a personal stake in it. What surprised me most is that sperm health appears to be about much more than conception. It tracks with metabolic health, immune health, pregnancy outcomes, and in one Danish cohort, with age of death decades later.

What We Cover

  • What a semen analysis measures, and why ejaculating normally tells you nothing
  • Semen quality as a sixth vital sign, and the Danish study linking it to lifespan
  • Testosterone therapy, why it functions as a contraceptive, and how long recovery takes
  • Whether sperm counts are really declining, and the likely drivers
  • Cannabis, alcohol, heat, cycling, sleep, and body weight
  • Total motile sperm count, DNA fragmentation, and what to ask your lab for
  • Paternal age, sperm freezing, and timing your decisions

Sperm turn over roughly every three months, which makes this one of the most movable metrics in health. Whichever stage of life you're at, this conversation is worth your time.

To connect with Dr Michael Eisenberg, find him on Instagram or LinkedIn. To connect with Dr Natalie Crawford, you can find her book The Fertility Formula at nataliecrawfordmd.com/book, listen to her podcast As a Woman, or follow her on Instagram, TikTok, YouTube, and LinkedIn.

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