Sperm concentration among men in Western countries dropped 51.6 percent between 1973 and 2018, from 101 million per milliliter to 49 million per milliliter (Levine et al., Human Reproduction Update, 2023). That study mapped the trend. It did not test chemicals. A separate line of research is working out how environmental pollutants like BPA and certain pesticides may contribute to that decline.
The short answer is that these chemicals can interfere with the hormonal signals and physical processes sperm production depends on. The longer answer matters more because the effects are slow, cumulative, and often tied to avoidable exposures.
How endocrine disruption works
BPA and many pesticides belong to a group called endocrine disrupting chemicals, or EDCs. They can mimic or block natural hormones, especially estrogen and testosterone. The testes are sensitive to those signals. When an outside chemical occupies a hormone receptor, it can change how much testosterone the Leydig cells produce or how sperm cells mature.
The result does not show up immediately. Sperm production takes about seventy days, so an exposure today may appear in a semen analysis two to three months later. That delay is one reason men often miss the connection between daily chemical exposure and a lower count.
BPA sources and what the research shows
BPA is used in polycarbonate plastics, the epoxy linings of some canned foods, and thermal paper receipts. It migrates into food and drink faster when the container is hot or the contents are acidic. Tomato sauce in a heated can liner is a bigger source than a room-temperature bottle of water.
Inside the body, BPA is metabolized quickly and leaves through urine within a day. That sounds reassuring, but most people are exposed daily, so their bodies never get a break. Urinary BPA levels measure continuous intake, not a single meal.
A 2024 meta-analysis in Toxics pooled observational studies on BPA and semen quality (Lu et al., 2024). Men with higher urinary BPA tended to have lower sperm concentration and reduced motility in several of those studies. The work was cross-sectional, meaning researchers measured exposure and sperm quality at the same time. That design cannot prove cause and effect. Animal studies add support. Rodents exposed to BPA during development show changes in testicular structure and lower sperm production, although the doses are often higher than typical human exposure.
Manufacturers who removed BPA often switched to BPS or BPF. Those substitutes have similar chemical structures. Early research suggests they may have similar endocrine activity. Reduce contact with polycarbonate plastics and thermal paper. That route avoids both BPA and several of its substitutes.
Pesticides: persistent and current-use
Pesticide research splits into two buckets. Organochlorine pesticides, including DDT and its metabolite DDE, were banned in many countries decades ago but persist in soil, water, and fatty tissue. They can remain in the body for years. Organophosphate pesticides, including chlorpyrifos and malathion, are still used in agriculture in many regions. They break down faster but are common enough that diet and water expose many people.
A 2021 review in Frontiers in Endocrinology summarized the state of the field for EDCs and male reproductive health (Rodprasert, Toppari, and Virtanen, 2021). Studies of pesticide applicators and agricultural workers, who receive the highest doses, report lower sperm counts and altered hormone levels more consistently than studies of the general population. In general-population studies, some urinary pesticide markers track with lower sperm motility and higher sperm DNA fragmentation, but results vary by compound and population.
DDT was banned in the United States in 1972, yet its metabolite DDE still appears in blood samples today. Several studies have linked higher DDE levels to reduced sperm motility. The picture is not uniform. Men with higher DDE also tend to be older or eat diets that differ in other ways, which makes isolation difficult. Occupational studies remain the clearest evidence because the exposure is higher and easier to measure.
What over time actually means
Over time matters in two ways. Some pollutants accumulate. Organochlorine pesticides are lipophilic (they store in body fat). When body fat is metabolized, those chemicals can re-enter circulation. Even chemicals that clear quickly, like BPA, can have chronic effects if exposure never stops.
The second factor is cell division. Sperm cells divide frequently, which makes them more sensitive to DNA damage. The testicles also depend on a precise hormone and temperature range. Chronic low-dose endocrine disruption may reduce the number of healthy sperm produced each cycle. A man can feel fine and still have a lower count. A semen analysis is the standard way to find out.
What the evidence cannot prove
Human studies cannot isolate BPA or one pesticide from the hundreds of chemicals a person encounters every day. Most of the research is observational. Researchers measure exposure and semen quality in the same person, adjust for age, smoking, weight, and other factors, and look for patterns, but that design cannot prove one chemical caused the result.
Animal studies give clearer proof that BPA and many pesticides can damage testicular tissue and reduce sperm, but those doses are often far above everyday human exposure. The strongest human data come from occupational settings. Everyday background exposure is linked to smaller effects, and some studies find no effect at all. The pattern across studies is consistent enough to justify reducing contact where it is low cost. The precision matters because it tells you which changes are likely to help and which are guesswork.
Reducing your daily exposure
For most men, food and drink are the biggest everyday routes for BPA and many pesticides. These changes target those routes without turning daily life into a chemistry project.
- Heat and store food in glass or stainless steel instead of plastic. Heating plastic raises migration of BPA and phthalates. Do not microwave food in plastic containers.
- Cut back on canned food when fresh or frozen options exist. Acidic canned foods like tomatoes are more likely to pick up liner chemicals.
- Wash and scrub produce under running water. Scrubbing removes more surface pesticide residue than rinsing alone. Peeling helps for thick-skinned produce, though it also removes fiber and nutrients.
- For high-residue conventional crops, buying organic can lower measurable pesticide metabolites in urine. Organic does not mean pesticide-free, but the difference shows up in exposure studies.
- If you handle pesticides at work or on a farm, use the protective equipment on the label. Remove work clothes before sitting on furniture or entering your bedroom. Wash them separately.
- Wash your hands after touching thermal paper receipts. BPA and BPS on receipts can sit on skin and absorb through it. If your water has tested positive for pesticides, a carbon filter or reverse osmosis system can reduce several contaminants.
When to get a semen analysis
If you are planning to conceive, a semen analysis gives you a better read than tracking chemical exposures. It measures sperm count, motility, and morphology under standard conditions. A reproductive urologist or men's health doctor can interpret the result and look at the whole picture, including sleep, alcohol, weight, medication, and temperature exposure.
The useful move is to reduce the exposures you control and get the right test when it matters. Most men never hear how much environmental exposure is within their control. That is the part worth acting on.
This content is for educational purposes only and is not medical advice. Oakman products are designed for physical comfort and cooling. They make no claims about fertility, sperm quality, or hormone levels. Consult a healthcare professional for personalized advice.