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Falling fertility rates — and what clothes have to do with it
Fertility rates are declining across the globe. While age, stress, and diet all play a role, researchers are also uncovering another quiet influence: what we wear every day.
Synthetic fabrics like polyester, nylon, and spandex dominate modern wardrobes. They’re stretchy, cheap, and everywhere — but they also shed microplastics and are often treated with toxic chemical coatings that can affect reproductive health in both men and women.
Polyester: the curious fertility experiment
In the 1990s, Dr. Ahmed Shafik conducted unusual studies showing that men wearing polyester fabric directly against the scrotum became temporarily infertile. He suggested two mechanisms:
- Heat retention — polyester traps warmth, raising testicular temperature, which is known to impair sperm production.
- Electrostatic “fabric frequency” — polyester rubbing on skin generates static charge, possibly disrupting cell function.
Although the research was small and never widely repeated, it raised an important point: our clothes interact with our biology. [1]
Polyester and fertility in dogs
The link between polyester and fertility wasn’t just observed in men. In 2008, researchers studied 35 female dogs dressed in undergarments made from different fabrics — polyester, polyester–cotton blends, cotton, and wool — over the course of a year.
The results were striking: the dogs in polyester and polyester-blend garments showed a drop in progesterone during their reproductive cycle and failed to conceive, whether through natural mating or insemination. Researchers even detected electrostatic fields on the skin of the polyester-wearing dogs, suggesting that the fabric’s electrical charge might interfere with reproductive function.
The good news? The effects were reversible. Within five months of removing the polyester garments, hormone levels returned to normal and the dogs were able to conceive successfully. [2]
The real modern concern: coatings, chemicals & microplastics
Today’s science points less to the fabric itself, and more to the chemicals that cling to synthetics:
PFAS (“forever chemicals”)
- Used in stain- and water-repellent finishes.
- Linked to reduced fertility, lower IVF success rates, endometriosis, and miscarriage risk. [3]
- Once in the body, PFAS can persist for years.
Phthalates & BPA
- Found in prints, plasticisers, and coatings.
- Known endocrine disruptors, interfering with hormone balance.
- Studies show associations with reduced sperm quality, lower testosterone, and increased miscarriage risk. [4]
Microplastics
- Studies in 2024–2025 detected microplastics (including polyester and PVC) in human testes, semen, and ovarian follicular fluid. [5] [6]
- Animal research shows microplastics can cause inflammation, DNA damage, and impaired fertility.
- Every time we wash synthetic activewear, we release microplastic fibres into our waterways — and ultimately, our bodies.
Fabric “frequency” and natural alternatives
Beyond chemical coatings and microplastics, there’s also the intriguing idea of fabric frequency. A study cited in our Frequency of Clothing: What Fabrics Support Your Health? blog explored how synthetics might drain energy, while natural fibres resonate more vibrantly.
Dr. Heidi Yellen found that polyester can generate static—and even tied to visualised “low-frequency” signatures—hinting at deeper impacts when we wear it close to the body.
Synthetics carry static, feel heavy, and shed plastic. Natural fibres—hemp, linen, organic cotton—are breathable, grounding, and biodegradable:
- They don’t shed microplastics.
- They don’t require endocrine-disrupting finishes as they are naturally breathable and moisture wicking.
- They allow your body to regulate its own temperature naturally.
Choosing natural is a higher-vibration choice—for your body, your practice, and the planet.
Where ZONE fits in: reimagining activewear
Major fashion brands know the risks — yet they continue to produce polyester-heavy activewear because it’s cheap and easy. At ZONE, we’ve chosen a harder path: reimagining non toxic activewear with natural fibres first.
100% Natural, No Synthetics: Hemp Clothing Australia
- Hemp t shirts & tanks: Breathable, grounding, and free from spandex or polyester.
- Hemp Joggers & Hoodies: Hemp and organic cotton blends that soften with every wash.
- Hemp Linen Sets: Lightweight, timeless, and toxin-free.
These pieces are synthetic-free — no microplastic shedding, no chemical coatings, no hidden toxins.
Natural with 5% Spandex (for movement)
- Hemp Leggings & Yoga Pants Australia — supportive, high-waisted, and breathable. Designed for mindful, low-tox movement with only 5% spandex for natural stretch.
- Hemp Sports Bras — naturally breathable and skin-friendly, offering light-to-medium support without the toxins of polyester-based activewear.
- Hemp Bike Shorts — with dual side pockets, moisture-wicking hemp fabric, and a fit that keeps you fresh between washes.
Low-Tox Yoga Accessories
-
Eco Yoga Mat & Yoga Blocks — made from cork and natural rubber with no harsh glues or chemicals. A sustainable alternative to the PVC mats that dominate the market.
How to lower your exposure
- Choose natural fibres first. Swap polyester tees for hemp T-shirts and linen sets.
- Minimise synthetics. When you need stretch, opt for blends with <5% spandex.
- Avoid PFAS finishes. Skip “stain-resistant” or “water-repellent” labels unless they are verified PFAS-free.
- Wash smart. Use cooler cycles, liquid detergent, and a microfibre filter or wash bag.
The bottom line
Clothing alone doesn’t explain declining fertility, but the evidence is growing: PFAS, phthalates, BPA, and microplastics from synthetic fabrics are showing up in human reproductive tissues — and that should raise concern.
The early polyester studies hinted at a link between fabric and fertility. Today’s science shows us it’s less about the fibres themselves, and more about the chemical load and plastic shedding they carry.
By choosing natural, renewable fibres like hemp and linen, you’re not just making a style statement. You’re making a fertility-friendly, planet-friendly choice.
Explore the higher-frequency choice with ZONE by Lydia — Hemp Clothing Australia
If you’ve been looking for non toxic activewear, yoga clothes Australia, or sustainable alternatives like yoga leggings AU, we’re here to help. Our mission is to provide low-tox, high-quality pieces that last:
- Hemp t shirts — breathable, everyday basics with no synthetics.
- Hemp Leggings, Bike Shorts, Yoga Pants & Sports Bras — performance wear with only 5% spandex for stretch.
- 100% Hemp Linen Sets — timeless, 100% natural comfort.
- Cork & Natural Rubber Yoga Mat - Made with natural rubber and cork with no harsh chemicals or glues.
Footnotes
- Shafik, A. Contraceptive efficacy of polyester-induced azoospermia in normal men. Contraception. 1992. PubMed ↩
- Shafik, A. An experimental study on the effect of different types of textiles on conception. Urologic Research. 2008. PubMed ↩
- Mount Sinai. Exposure to chemicals found in everyday products is linked to significantly reduced fertility. 2023. Mount Sinai News ↩
- National Institute of Environmental Health Sciences. Phthalates and Bisphenol A (BPA). Updated 2024. NIEHS ↩
- UNM Health Sciences. Microplastics found in every human and canine testicle examined. Toxicological Sciences, 2024. UNM News ↩
- ESHRE / Human Reproduction. Microplastics detected in human semen and ovarian follicular fluid. 2025. EurekAlert ↩
