Reproductive Health
Toxins and fertility — a toxic relationship
Sperm counts have halved in half a century. The chemistry behind that trend reaches both sexes, and it works through the hormonal signalling that governs reproduction itself.
Sperm counts and semen quality have fallen sharply over the past half-century. A landmark meta-analysis found an approximately 50% drop in sperm concentration among men from industrialised regions between 1973 and 2011, driven by a 50–60% decline among men unselected for fertility in North America, Europe, Australia and New Zealand — a decline that has continued into the 21st century (Levine et al., 2017; Stavros et al., 2025).
Worldwide, infertility affects around 8–12% of couples, with male factors identified as the primary cause in about half of cases (Kumar & Singh, 2022). How much of the sperm decline is attributable to endocrine-disrupting chemicals is not precisely known, but the contribution is judged substantial.
Chemicals that impersonate hormones
The core mechanism is endocrine disruption: many pollutants mimic or block sex hormones — showing estrogenic, anti-estrogenic, androgenic or anti-androgenic activity — and so interfere with the hormonal signalling that governs reproduction (Carpenter et al., 1998). Rising male infertility has been linked to heavy metals, phthalates, pesticides and BPA acting through oxidative stress, apoptosis, disrupted estrogen and androgen signalling, interference with the hypothalamic–pituitary–gonadal axis, and heritable epigenetic changes (Stavros et al., 2025).
Testosterone down, the signal to compensate up
The hormonal signature of exposure is visible in pooled data: exposure to endocrine disruptors was associated with a 28.5% decrease in testosterone, alongside compensatory rises in FSH (+45.2%) and LH (+38.9%) (Han & Jin, 2025) — the pattern of a system straining to drive a gonadal response it is no longer getting.
Near-universal exposure, dose-related harm
It is not debatable that BPA disrupts sperm production: it acts as an androgen-receptor antagonist and impairs Leydig-cell steroidogenesis (Matuszczak et al., 2019). What makes it consequential is how widely it is carried. Among couples seeking infertility treatment, BPA was found in the urine of 98% of patients, and its level correlated negatively with sperm count and motility (Matuszczak et al., 2019); a Spanish study of 215 young men detected it in 95% of samples and found a significant negative association with sperm count (Adoamnei et al., 2018b).
BPA exposure is linked to sperm DNA damage, reduced motility and count, and oxidative stress — the most common cause of sperm damage (Kumar & Singh, 2022; Matuszczak et al., 2019).
A named syndrome, and a measurable bill
Phthalates produce a cluster of effects termed "phthalate syndrome": diminished anogenital distance, low sperm count, undescended testes, hypospadias and other reproductive-tract anomalies (Kumar & Singh, 2022). Reduced sperm quality is probably the most consistently observed effect of phthalate exposure (Chang et al., 2021), with most studies reporting negative associations with at least one — often several — semen-quality parameters (Kahn et al., 2020). They act largely by inhibiting Leydig-cell testosterone synthesis (Mallozzi et al., 2016).
The economic estimate is correspondingly large: male infertility attributable to phthalate exposure had a 40–69% probability of causing 618,000 additional assisted-reproduction procedures annually in Europe, alongside lower testosterone in older men linked to 24,800 deaths a year (Trasande et al., 2015).
Metals, pesticides, PFAS and particles
Lead and cadmium are known reproductive toxicants and suspected endocrine disruptors that impair semen quality (Kumar & Singh, 2022). Cadmium compromises the blood–testis barrier, blocks calcium channels needed for fertilisation and reduces motility; lead destabilises sperm, lowers testosterone and, above blood levels of 10 µg/dL, produces significant sperm DNA damage (Koyama, Kamogashira & Yamasoba, 2024; Han & Jin, 2025). Mercury exposure induced sperm DNA damage and abnormal morphology and motility, with infertile men showing higher mercury in hair, blood and urine than fertile men (Henriques et al., 2019).
Pesticide exposure impairs spermatogenesis, reducing concentration and motility and increasing abnormal forms (Kumar & Singh, 2022); organophosphates are consistently associated with reduced semen quality (Kahn et al., 2020); and DDT and its metabolite DDE — still detectable decades after being banned — remain anti-androgenic and continue to disrupt testosterone synthesis (Han & Jin, 2025). PFAS exposure impairs motility and is linked to lower sperm concentration and count and higher LH and FSH in young men (Fenton et al., 2021), with PFNA in particular inversely correlated with testosterone (Rahman, Stokey & Munson-McGee, 2026). Microplastics have been detected in human semen and are linked to reduced fertility via inflammation and oxidative stress (Barceló, Picó & Alfarhan, 2023; Liu et al., 2026), and fine particulate air pollution is significantly associated with decreased concentration, motility and normal morphology, and increased sperm DNA fragmentation (Kumar & Singh, 2022).
Ovarian and uterine toxicity — reaching forward
Endocrine disruptors are increasingly shown to shorten gestation, alter fetal growth and disrupt metabolic programming (Minderoo-Monaco Commission, 2023), with a comprehensive overview linking them to a range of female reproductive disorders (Crain et al., 2008). BPA is judged both an ovarian and a uterine toxicant: it affects the onset of egg-cell development, accelerates follicle transition, alters steroidogenesis, reduces oocyte quality in women undergoing IVF, and impairs uterine receptivity while increasing implantation failure in animal models — the overall conclusion being that it is a reproductive toxicant (Peretz et al., 2014).
Most striking is how far forward the effect reaches. Maternal BPA exposure affects the earliest stages of egg formation in the developing female fetus, so meiotic defects can make that fetus’s own future embryos chromosomally abnormal in adulthood — an effect spanning generations (Mallozzi et al., 2016).
Miscarriage, PCOS and the metals
Serum BPA was about three times higher in women with a history of three or more consecutive first-trimester miscarriages than in women without fertility problems (Meeker, Sathyanarayana, Swan, 2009).
Women with polycystic ovary syndrome likewise had higher serum BPA than women without it (Meeker, Sathyanarayana, Swan, 2009), with six cross-sectional studies reporting positive associations between BPA and PCOS (Kahn et al., 2020); BPA has also been associated with recurrent miscarriage and more premature births (Matuszczak et al., 2019). Among metals, cadmium can cause hormonal abnormalities and infertility in women and is linked to low birth weight, premature delivery and spontaneous miscarriage (Vijiyakumar & Prince, 2024), while mercury was associated with menstrual and hormonal disorders, reduced fecundability, longer time-to-pregnancy and adverse reproductive outcomes, with the risk of spontaneous abortion rising significantly as concentrations increased (Henriques et al., 2019). And the herbicide atrazine demasculinises and feminises the gonads of male vertebrates across every vertebrate class examined — a case its authors argue meets all nine Bradford Hill criteria for causation (Hayes et al., 2011).
Testicular dysgenesis syndrome
Much of this converges on a single idea: that anti-androgenic exposures in the womb produce a linked set of male reproductive problems — reduced anogenital distance, cryptorchidism, hypospadias and poor semen quality. Anogenital distance measured at birth tracks into adulthood and predicts infertility and reduced sperm count (Minderoo-Monaco Commission, 2023), and prenatal DEHP exposure has been inversely related to anogenital distance, penile width and testicular descent in male offspring (Thompson et al., 2009; Meeker, Sathyanarayana, Swan, 2009). On this reading, adult infertility is often the late expression of an exposure that happened before birth.
What the evidence supports — and the honest caveats
Two caveats are preserved within the findings themselves. First, the evidence is stronger in animals and in mechanism than in human causal proof: the cumulative effects of multiple endocrine disruptors, the critical exposure windows, and long-term human reproductive effects remain unknown, and are complicated by non-monotonic dose–response and mixture effects (Stavros et al., 2025). Second, results are not always consistent. For mercury, some studies found no association, and one even found better semen quality at higher mercury levels among men with high fish intake — likely an omega-3 benefit — so the data suggest only weak negative associations with male fertility markers (Henriques et al., 2019). Parabens, in a Spanish study of 215 young men, showed no significant negative effect on reproductive parameters (Adoamnei et al., 2018).
So the accurate reading is a broad, biologically coherent, and in places strong association between many common pollutants and impaired fertility in both sexes — most robust for phthalates, BPA and the sperm-quality endpoints — rather than settled single-cause proof for every chemical.
A summary of findings from the referenced scientific literature. Not medical advice.
Sources
Adoamnei et al., 2018 — Evdochia Adoamnei, Jaime Mendiola, Miriam Moñino-García, Fernando Vela-Soria, Luz M. Iribarne-Durán, Mariana F. Fernández, Nicolás Olea, Niels Jørgensen, Shanna H. Swan, Alberto M. Torres-Cantero: Urinary concentrations of parabens and reproductive parameters in young men, Science of the Total Environment, 621, 2018; DOI: 10.1016/j.scitotenv.2017.11.256.
Adoamnei et al., 2018b — Evdochia Adoamnei, Jaime Mendiola, Fernando Vela-Soria, Mariana F. Fernández, Nicolás Olea, Niels Jørgensen, Shanna H. Swan, Alberto M. Torres-Cantero: Urinary bisphenol A concentrations are associated with reproductive parameters in young men, Environmental Research, 161, 2018; DOI: 10.1016/j.envres.2017.11.002.
Barceló, Picó, Alfarhan, 2023 — Damià Barceló, Yolanda Picó, Ahmed H. Alfarhan: Microplastics: Detection in human samples, cell line studies, and health impacts, Environmental Toxicology and Pharmacology, 101, 2023; DOI: 10.1016/j.etap.2023.104204.
Carpenter et al., 1998 — David O. Carpenter, Kathleen F. Arcaro, Brian Bush, William D. Niemi, Shaokun Pang, Dilip D. Vakharia: Human Health and Chemical Mixtures. An Overview, Environmental Health Perspectives, Vol. 106, Supp. 6, 1998.
Chang et al., 2021 — Wei-Hsiang Chang, Samuel Herianto, Ching-Chang Lee, Hsin Hung, Hsiu-Ling Chen: The effects of phthalate ester exposure on human health: A review, Science of the Total Environment, 786, 2021; DOI: 10.1016/j.scitotenv.2021.147371.
Crain et al., 2008 — D. Andrew Crain, Sarah J. Janssen, Thea M. Edwards, Jerrold Heindel, Shuk-mei Ho, Patricia Hunt, Taisen Iguchi, Anders Juul, John A. McLachlan, Jackie Schwartz, Niels Skakkebaek, Ana M. Soto, Shanna Swan, Cheryl Walker, Teresa K. Woodruff, Tracey J. Woodruff, Linda C. Giudice, Louis J. Guillette Jr.: Female reproductive disorders: the roles of endocrine-disrupting compounds and developmental timing, Fertility and Sterility, Vol. 90, No. 4, 2008; DOI: 10.1016/j.fertnstert.2008.08.067.
Fenton et al., 2021 — Suzanne E. Fenton, Alan Ducatman, Alan Boobis, Jamie C. DeWitt, Christopher Lau, Carla Ng, James S. Smith, Stephen M. Roberts: Per- and Polyfluoroalkyl Substance Toxicity and Human Health Review. Current State of Knowledge and Strategies for Informing Future Research, Environmental Toxicology and Chemistry, Vol. 40, No. 3, 2021; DOI: 10.1002/etc.4890.
Han, Jin, 2025 — Xiaoyan Han, Xiaolong Jin: The impact, mechanisms and prevention strategies of environmental endocrine disruptors on male reproductive health, Front. Endocrinol., 16, 2025; DOI: 10.3389/fendo.2025.1573526.
Hayes et al., 2011 — Tyrone B. Hayes, Lloyd L. Anderson, Val R. Beasley, Shane R. de Solla, Taisen Iguchi, Holly Ingraham, Patrick Kestemont, Jasna Kniewald, Zlatko Kniewald, Valerie S. Langlois, Enrique H. Luque, Krista A. McCoy, Mónica Muñoz-de-Toro, Tomohiro Oka, Cleida A. Oliveira, Frances Orton, Sylvia Ruby, Miyuki Suzawa, Luz E. Tavera-Mendoza, Vance L. Trudeau, Anna Bolivar Victor-Costa, Emily Willingham: Demasculinization and feminization of male gonads by atrazine: Consistent effects across vertebrate classes, Journal of Steroid Biochemistry & Molecular Biology, 127, 2011; DOI: 10.1016/j.jsbmb.2011.03.015.
Henriques et al., 2019 — Magda Carvalho Henriques, Susana Loureiro, Margarida Fardilha, Maria Teresa Herdeiro: Exposure to mercury and human reproductive health. A systematic review, Reproductive Toxicology, 85, 2019; DOI: 10.1016/j.reprotox.2019.02.012.
Kahn et al., 2020 — Linda G. Kahn, Claire Philippat, Shoji F. Nakayama, Rémy Slama, Leonardo Trasande: Endocrine-disrupting chemicals. Implications for human health, Lancet Diabetes Endocrinol., 8(8), 2020; DOI: 10.1016/S2213-8587(20)30129-7.
Koyama, Kamogashira, Yamasoba, 2024 — Hajime Koyama, Teru Kamogashira, Tatsuya Yamasoba: Heavy Metal Exposure: Molecular Pathways, Clinical Implications, and Protective Strategies, Antioxidants, 2024, 13, 76; DOI: 10.3390/antiox13010076.
Kumar, Singh, 2022 — Naina Kumar, Amit Kant Singh: Impact of environmental factors on human semen quality and male fertility: a narrative review, Environmental Sciences Europe, 2022, 34(6); DOI: 10.1186/s12302-021-00585-w.
Levine et al., 2017 — Hagai Levine, Niels Jørgensen, Anderson Martino-Andrade, Jaime Mendiola, Dan Weksler-Derri, Irina Mindlis, Rachel Pinotti, Shanna H. Swan: Temporal trends in sperm count: a systematic review and meta-regression analysis, Human Reproduction Update, Vol. 23, No. 6, 2017; DOI: 10.1093/humupd/dmx022.
Liu et al., 2026 — Jianhui Liu, Shaofei Su, Ruixia Liu, Shuanghua Xie, Chenghong Yin, Enjie Zhang, Lihua Ren: Polystyrene nanoplastics disrupted cholesterol/testosterone homeostasis via Smurf1-dependent FTO degradation, Food and Chemical Toxicology, 209, 2026; DOI: 10.1016/j.fct.2025.115926.
Mallozzi et al., 2016 — Maddalena Mallozzi, Giulia Bordi, Chiara Garo, Donatella Caserta: The Effect of Maternal Exposure to Endocrine Disrupting Chemicals on Fetal and Neonatal Development. A Review on the Major Concerns, Birth Defects Research, 2016; DOI: 10.1002/bdrc.21137.
Matuszczak et al., 2019 — Ewa Matuszczak, Marta Diana Komarowska, Wojciech Debek, Adam Hermanowicz: The Impact of Bisphenol A on Fertility, Reproductive System, and Development. A Review of the Literature, International Journal of Endocrinology, 2019; DOI: 10.1155/2019/4068717.
Meeker, Sathyanarayana, Swan, 2009 — John D. Meeker, Sheela Sathyanarayana, Shanna H. Swan: Phthalates and other additives in plastics: human exposure and associated health outcomes, Phil. Trans. R. Soc. B, 2009, 364; DOI: 10.1098/rstb.2008.0268.
Minderoo-Monaco Commission, 2023 — P. J. Landrigan, H. Raps, M. Cropper, C. Bald, M. Brunner, E. M. Canonizado, D. Charles, T. C. Chiles, M. J. Donohue, J. Enck, P. Fenichel, L. E. Fleming, C. Ferrier-Pages, R. Fordham, A. Gozt, C. Griffin, M. E. Hahn, B. Haryanto, R. Hixson, H. Ianelli, B. D. James, P. Kumar, A. Laborde, K. L. Law, K. Martin, J. Mu, Y. Mulders, A. Mustapha, J. Niu, S. Pahl, Y. Park, M.-L. Pedrotti, J. A. Pitt, M. Ruchirawat, B. J. Seewoo, M. Spring, J. J. Stegeman, W. Suk, C. Symeonides, H. Takada, R. C. Thompson, A. Vicini, Z. Wang, E. Whitman, D. Wirth, M. Wolff, A. K. Yousuf, S. Dunlop: The Minderoo-Monaco Commission on Plastics and Human Health, Annals of Global Health, 2023, 89(1); DOI: 10.5334/aogh.4056.
Peretz et al., 2014 — Jackye Peretz, Lisa Vrooman, William A. Ricke, Patricia A. Hunt, Shelley Ehrlich, Russ Hauser, Vasantha Padmanabhan, Hugh S. Taylor, Shanna H. Swan, Catherine A. VandeVoort, Jodi A. Flaws: Bisphenol A and Reproductive Health: Update of Experimental and Human Evidence, 2007–2013, Environ Health Perspect, 122, 2013; DOI: 10.1289/ehp.1307728.
Rahman, Stokey, Munson-McGee, 2026 — Humairat H. Rahman, Weston R. Stokey, Stuart H. Munson-McGee: Correlation of per- and poly-fluoroalkyl substances (PFAS) exposure with testosterone levels in the male population, Environmental Toxicology and Pharmacology, 121, 2026; DOI: 10.1016/j.etap.2025.104906.
Stavros et al., 2025 — Sofoklis Stavros, Nikolaos Kathopoulis, Efthalia Moustakli, Anastasios Potiris, Ismini Anagnostaki, Spyridon Topis, Nefeli Arkouli, Konstantinos Louis, Charalampos Theofanakis, Themos Grigoriadis, Nikolaos Thomakos, Athanasios Zikopoulos: Endocrine-Disrupting Chemicals and Male Infertility: Mechanisms, Risks, and Regulatory Challenges, J. Xenobiot., 2025, 15, 165; DOI: 10.3390/jox15050165. Listed as "Stavroz et al." in the source’s literature section; the first author’s name is Sofoklis Stavros.
Thompson et al. 2009 — Richard C. Thompson, Charles J. Moore, Frederick S. vom Saal, Shanna H. Swan: Plastics, the environment and human health: current consensus and future trends, Phil. Trans. R. Soc. B, 2009, 364; DOI: 10.1098/rstb.2009.0053.
Trasande et al., 2015 — Leonardo Trasande, R. Thomas Zoeller, Ulla Hass, Andreas Kortenkamp, Philippe Grandjean, John Peterson Myers, Joseph DiGangi, Martine Bellanger, Russ Hauser, Juliette Legler, Niels E. Skakkebaek, Jerrold J. Heindel: Estimating Burden and Disease Costs of Exposure to Endocrine-Disrupting Chemicals in the European Union, J Clin Endocrinol Metab, 2015; DOI: 10.1210/jc.2014-4324.
Vijiyakumar, Prince, 2024 — Naveen Vijiyakumar, Sabina Evan Prince: A comprehensive review of cadmium-induced toxicity, signalling pathways, and potential mitigation strategies, Toxicology and Environmental Health Sciences; DOI: 10.1007/s13530-024-00243-7.