Testosterone & Sperm Counts In Freefall: Dr. Thinks Key Culprit Is Phthalates

Dr. Andrew Huberman attended a popular science talk in Copenhagen’s concert hall, with a gripped audience listened intently to Dr. Shanna Swan discuss a startling decline in testosterone levels and sperm counts.

Her message: We should be very worried.

Two Decades of Research Confirm the Decline

Swan has studied falling sperm counts for over 20 years. In the 1990s, she initially doubted claims of a major decline. But upon closely analyzing 61 studies, she found sperm counts had plunged 50-60% between 1973 and 2011 ¹.

It was a shockingly “stable result” that didn’t budge “to the first decimal place” after accounting for potential errors.

Since then, Swan’s research has only strengthened the sperm decline finding. In 2017, she published a seminal study with colleagues showing total sperm count has dropped 59% in just 39 years ².

Swan calls this the “1% effect” – a steady yearly decline of 1% in sperm and testosterone over generations. Miscarriages and fertility problems in women are rising at the same rate ³.

Dire Consequences for Fertility & Society

The implications are dire. By 2050, this may mean most men may be infertile.

Developed countries face inverted population pyramids, with swelling elderly populations supported by shrinking young workforces. The world fertility rate has halved from 5 children per couple in 1960 to 2.3 today.

fertility rates

Genetics don’t explain the plunge. The finger points to “hormone hacking” chemicals called endocrine disruptors.

These hijack the body’s hormone system, interfering with testosterone and fertility.

Phthalates In Plastics are a Key Culprit

Phthalates , which soften plastics, are a leading culprit. Rodent studies show phthalate exposure in utero shrinks male genitalia and reduces testosterone. Swan’s research found the same “phthalate syndrome” in baby boys whose mothers had high phthalate levels during pregnancy.

They had shorter anogenital distances, signaling lower testosterone exposure in the womb.

Animal studies reveal this spells trouble later in life. Male rats exposed to phthalates prenatally grow into subfertile adults even if their environment is cleaned up.

Similarly, men with shorter anogenital distances often have genital birth defects, testicular cancer and low sperm counts.

The verdict is in: phthalate exposure in the womb damages male reproductive health for decades after.

Phthalates Are Ubiquitous, But Avoidable

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Image Credit: MOHAMED ABDULRAHEEM/ShutterStock.

Phthalates lurk everywhere – plastics, vinyl products, tubing, personal care products, pesticides. BPA, another hormonal chemical, lines tin cans and plastic bottles.

Hundreds of stealthy hormone hackers swarm our bodies.

Reason for Hope

The good news is phthalates quickly exit the body once exposure stops. And rodent studies show reproductive function can be restored in three generations after environmental cleanup.

So while the clock is ticking on male fertility, small steps to minimize hormone hackers now offer hope of reversing this crisis for our sons and grandsons.


This article was originally published on, and syndicated by Viral Chatter.

  1. ncbi.nlm.nih.gov/pmc/articles/PMC6455044/
  2. academic.oup.com/humupd/article/23/6/646/4035689
  3. /pubmed.ncbi.nlm.nih.gov/29053188/
  4. cdc.gov/biomonitoring/Phthalates_FactSheet.html
  5. pubmed.ncbi.nlm.nih.gov/16102138/

Here are a couple of videos of Dr. Andrew Huberman and Dr. Shanna Swan discussing this:

Martha A. Lavallie
Martha A. Lavallie
Author & Editor | + posts

Martha is a journalist with close to a decade of experience in uncovering and reporting on the most compelling stories of our time. Passionate about staying ahead of the curve, she specializes in shedding light on trending topics and captivating global narratives. Her insightful articles have garnered acclaim, making her a trusted voice in today's dynamic media landscape.