Researchers Find The Same Chemicals Wrecking Wildlife Fertility In Humans
Female mud snails are developing male reproductive organs near marinas. In Florida, alligators living in lakes contaminated with pesticides are being born with smaller genitals and disrupted hormones. Sea turtle populations are becoming almost entirely female as nesting sands get warmer. The same types of chemicals responsible for these wildlife changes are now found in human placentas, testes, and semen. A new peer-reviewed review brings all of this evidence together for the first time.
A cross-species review published April 23 in npj Emerging Contaminants, led by Oregon State University toxicologist Susanne Brander and Mount Sinai researcher Shanna Swan, brings together evidence from many animal groups, including invertebrates, fish, birds, reptiles, amphibians, marine mammals, rodents, and humans. The main finding is that pollution and climate change together are now the biggest single cause of biodiversity loss. The chemicals at the heart of this problem—phthalates, bisphenols, PFAS, and microplastics—are lowering fertility and reproductive success in many species, including humans.
Of more than 140,000 synthetic chemicals registered under the EU’s REACH chemical safety regulation, only about 1% have been properly tested for safety, and over 1,000 are known endocrine-disrupting chemicals (EDCs). Each year, more than 2,000 new chemicals are introduced worldwide. The review’s authors say these chemicals can be effective at concentrations so low they are “analogous to a whisper that is powerful enough to redirect a hurricane.” Because the endocrine system is very similar across vertebrates, scientists have used fish to predict effects in mammals. This is why the human findings in the review are not surprising when compared to what has happened in wildlife.
The article provides new clarity on how climate change and chemical exposure interact. Warmer temperatures have been shown to worsen endocrine disruption. In some fish, heat combined with EDCs changes sex ratios more than either factor alone. At the world’s largest green turtle rookery, almost all hatchlings are now female. In humans, an 80-year study of U.S. birth data found that hotter weather is linked to fewer conceptions. Other studies show that higher temperatures are connected to lower semen volume, sperm count, and sperm quality.
Plastics aren’t inert and “BPA-free” doesn’t mean safe
The article pays special attention to microplastics and nanoplastics, which were only recently recognized as reproductive toxicants. In 2021, researchers found microplastics in human placentas. In 2023, another study found microplastics in human testis and semen samples. A follow-up study found microplastics in every canine and human testis examined, with higher levels in humans. Several studies in the review show that polystyrene microplastics lower fertility, fertilization, and hatching rates in fish, and these effects can last for generations.
The issue of chemical substitution is important here as well. Older PFAS chemicals like PFOA have mostly been replaced, but their substitutes, such as GenX chemicals and other similar compounds, show equal or even stronger estrogen-like effects in lab tests. BPA substitutes like BPS and BPF act almost the same way on hormones. The review also points out that bio-based plastics like polylactic acid (PLA) caused reproductive harm in earthworms, similar to regular polyethylene. This pattern of “regrettable substitution,” where a banned chemical is swapped for a similar, unregulated one that causes the same harm, is now well documented.
The PFAS picture, in 2026
PFAS deserve their own paragraph because the regulatory ground is shifting. EPA’s most recent water testing data shows about 176 million Americans drink tap water contaminated with at least one PFAS compound. The CDC has detected PFAS in the blood of 99% of Americans tested, including newborns. PFAS are now linked to abnormal sperm in Arctic seabirds, in dogs, and in human cohort studies, with a recent systematic review of 30 studies covering nearly 28,000 participants finding moderately elevated odds of PCOS- and endometriosis-related infertility associated with PFAS exposure.
The federal regulatory response is the focus of much controversy. EPA finalized the first national drinking water limits for six PFAS in 2024, setting PFOA and PFOS at 4 parts per trillion. In May 2025, the agency announced it would keep those two limits but extend the compliance deadline to 2031, and eliminate limits on four other PFAS. In January 2026, the D.C. Circuit denied EPA’s request to summarily vacate those four limits; final briefs are due this spring, and a decision is expected in the second half of 2026. While that plays out, individual filtration is the only consumer-side lever that actually removes PFAS from the water already in the tap.
Individual actions alone cannot solve a problem this big. The review’s main point is that we need broad regulatory changes for whole classes of chemicals, not just one at a time. Still, you can lower your own exposure, and the most effective changes come from a few key steps. The list below is ordered by impact, not by how easy the steps are.
Drinking water: this is where to start
Start by checking your water. Enter your ZIP code into EWG’s Tap Water Database to find out what has been found in your local water supply. You can also use the EPA’s PFAS Analytic Tools for more information. If you have a private well, have it tested by an EPA-certified lab. Mail-in kits from SimpleLab and Cyclopure cost between $85 and $300.
Use a filter for your tap water. Choose filters that are certified to NSF/ANSI 53 (carbon-based) or NSF/ANSI 58 (reverse osmosis) for reducing PFAS. Be aware that “tested to NSF standards” is just a marketing term that can be abused, so check that the filter is actually certified. Reverse osmosis and granular activated carbon are proven to work, but most pitcher and refrigerator filters are not certified for PFAS.
Change filter cartridges on time. EWG senior scientist Tasha Stoiber points out that a used-up filter can release more PFAS than untreated tap water. Keeping up with the maintenance schedule is essential for protection.
Avoid using bottled water as a long-term fix. A 2024 Columbia University study found about 240,000 plastic particles per liter of bottled water, which is 10 to 100 times higher than earlier estimates. Around 90% of these particles are nanoplastics.
Food contact materials
Do not heat food in plastic containers. Phthalates are more likely to leach out when heated. Use glass or ceramic in the microwave. If you plan to reuse plastic food containers, avoid putting them through the dishwasher’s high-heat cycle.
Reduce takeout and fast food when possible. A 2016 study found that people who ate more fast food had higher levels of phthalate metabolites in their urine, likely due to plastic gloves, wraps, and containers. Maine will ban PFAS in food packaging starting in May 2026, with a wider ban by 2030. Other states are following Maine’s lead, but for now, eating fewer plastic-wrapped meals means less exposure.
Replace nonstick cookware when it becomes chipped or scratched, as it is damaged. PTFE-coated pans can release particles into food. Stainless steel, cast, good, long-lasting alternatives. Also, nonstick pans are not ideal for high-heat cooking like searing.
Store food in glass or stainless steel containers. This is the easiest change you can make. Glass jars and stainless containers do not release microplastics or phthalates and can last for decades. Replace plastic containers only when they break or stain, instead of buying more. products
Be cautious when you see the word “fragrance” on a product label. Diethyl phthalate (DEP) is often used as a fragrance carrier and does not have to be listed separately under U.S. labeling rules; it just appears as “fragrance” or “parfum.” Choose products that list all fragrance ingredients or are certified EWG VERIFIED or EPA Safer Choice.
Plug-in air fresheners are especially high in phthalates, so the easiest solution is to remove them and use ventilation instead.
Get rid of vinyl shower curtains. The “new shower curtain” smell comes from phthalates being released from PVC. Cotton, hemp, and PEVA shower curtains are easy to find and cost about the same as vinyl ones.
Check your cleaning products for parabens, triclosan, and APEs. EWG’s Guide to Healthy Cleaning rates products based on an EDC database. Laundry detergent and fabric softener residues stay on clothes and touch your skin for hours, so exposure can add up quickly.
Be careful with plastic toys labeled with codes 3, 6, or 7, especially for young children who put toys in their mouths. Code 3 is PVC, which contains phthalates. Code 6 is polystyrene. Code 7 is a general category that often includes polycarbonate, a source of BPA. Safer alternatives include wood, natural rubber, organic cotton, and silicone.
Stop pesticides at the property line.
Think twice before using pyrethroid-based treatments for your home or lawn. Bifenthrin, one of the most common pesticides in the U.S., has been shown to disrupt estrogen receptors in fish at levels often found in urban runoff after rain. The review also notes that people with higher levels of pyrethroid metabolites in their urine tend to have lower semen quality and more sperm DNA damage. If you hire a pest control service, ask about the active ingredients they use and request safer alternatives.
Buy organic for the produce items with the highest pesticide loads. EWG’s Shopper’s Guide to Pesticides in Produce (the “Dirty Dozen” / “Clean Fifteen”) lets you prioritize organic where it matters most, rather than treating the produce aisle as all-or-nothing.
Where individual action stops working
The authors of the review make it clear that consumer choices alone are not enough. These chemicals are found even in Arctic rainwater, can cross the placenta, and last for centuries in the environment. The solution they propose is coordinated regulatory action: a strong Global Plastics Treaty that targets harmful chemicals, not just plastics in general; regulations that cover whole classes of chemicals rather than one at a time; and rules that make polluters responsible for cleanup costs, rather than passing those costs to utilities and customers.
The reason the review looks at different species is to show that what happens to snails, alligators, and seabirds also happens to humans, just at a different pace. Wildlife data have been warning us for 40 years, and now human data are starting to show the same patterns.
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