Xenoestrogens earn their name from their structural resemblance to endogenous estrogens, the natural hormones that guide far more than reproduction. In the brain, estrogen signaling shapes neuronal differentiation, synaptic plasticity, neurotransmitter release, and the organization of sexually dimorphic circuits. Because xenoestrogens can bind estrogen receptors and hijack these pathways, they can mimic, amplify, or scramble hormonal instructions at concentrations far below those traditionally used in toxicological testing. The review emphasizes that these compounds frequently display non-monotonic dose-response curves, meaning that low doses can produce effects that are different, or even opposite, to those seen at high doses. That property upends a foundational assumption of classical toxicology, which has long held that the dose makes the poison.

The chemicals in question are everywhere. Bisphenol A, or BPA, leaches from plastic containers, food-can linings, and thermal receipts. Phthalates, added to plastics to make them flexible and durable, shed from personal care products, building materials, and countless household items. Polychlorinated biphenyls, or PCBs, were banned decades ago yet persist in soil, water, and animal tissue, bioaccumulating as they move up the food chain. Natural xenoestrogens such as phytoestrogens, found in certain plants, add a further layer of complexity. The result, the authors note, is chronic, low-dose, real-world exposure to a shifting cocktail of compounds whose combined effects remain poorly understood.

At the molecular level, the review describes several converging mechanisms of harm. BPA and certain PCBs bind estrogen receptors ERα and ERβ, triggering both genomic and rapid non-genomic signaling through pathways such as MAPK and PI3K/AKT, which govern cell proliferation, apoptosis, and differentiation. Xenoestrogens also disrupt the synthesis, transport, and metabolism of endogenous hormones by interfering with the hypothalamic-pituitary-gonadal axis, tilting the hormonal milieu that the developing brain depends on. Beyond receptor binding, these compounds perturb calcium signaling and glutamatergic neurotransmission by modulating NMDA receptor expression, a shift that can push neurons toward excitotoxicity and impair the precise wiring of synaptic connections.

Perhaps the most unsettling mechanism is epigenetic. Xenoestrogen exposure can induce aberrant DNA methylation and histone modifications, chemically rewriting the instructions that govern gene expression without changing the underlying DNA sequence. Among the genes affected are BDNF, SHANK3, and RELN, all of which are central to synaptic function and have been implicated in neurodevelopmental disorders such as autism spectrum disorder and attention-deficit/hyperactivity disorder. The downstream consequences include defects in synaptic pruning, neuronal migration, and myelination, the very processes that sculpt a mature, functional brain. Because epigenetic marks can be inherited, the review raises the possibility that today’s exposures may predispose future generations to neurodevelopmental vulnerability, a transgenerational shadow that conventional risk assessments have barely begun to address.

The behavioral evidence spans the laboratory and the wild. In rodent models, perinatal exposure to BPA, PCBs, and the synthetic estrogen diethylstilbestrol disrupts mating behavior by deranging the hypothalamic-pituitary-gonadal axis and altering estrogen and testosterone levels. Male rodents exposed to BPA early in life show reduced mounting and intromission frequencies, while females display altered estrous cyclicity and diminished lordosis responses. The sexually dimorphic nucleus of the preoptic area, normally larger in males, shrinks following early-life exposure to estrogenic disruptors, accompanied by disturbances in dopamine and oxytocin signaling that underpin sexual and affiliative behavior. In aquatic species, estrogenic pollutants have feminized male fish and amphibians, collapsing courtship behavior and reproductive success, with one landmark study documenting the collapse of an entire fish population after exposure to a synthetic estrogen.

Cognitive and emotional effects are equally well documented. The review links xenoestrogen exposure to impairments in learning, memory, and executive function, with implications for academic and professional performance, and to heightened anxiety, depression, and mood dysregulation, likely reflecting disruption of the limbic system. Social behavior is also affected, with altered social recognition, interaction, and communication observed across studies. Critically, many of these effects are sex-specific. Estrogen receptor subtypes are distributed differently in male and female brains, particularly in the hypothalamus, hippocampus, and amygdala, and male neurodevelopment depends heavily on the aromatization of testosterone into estradiol, creating distinct points of vulnerability. Prenatal BPA exposure, for example, has been associated with hypomethylation of the estrogen receptor alpha gene in the prefrontal cortex of female rodents but not males, correlating with increased anxiety-like behavior in females. The authors call for sex-stratified analyses to become standard practice in this field.

Timing magnifies the danger. The developing brain passes through tightly choreographed windows, spanning prenatal life, infancy, early childhood, and adolescence, when hormonal signals orchestrate the construction of neural circuits. Exposure during these periods can permanently alter brain structure, neuronal connectivity, and neurotransmitter systems, and the review links prenatal and early-childhood exposures to neurodevelopmental disorders, cognitive deficits, and behavioral abnormalities that persist into adulthood. Fetuses and infants are especially susceptible because their detoxification systems are immature and their brains are maximally plastic, while adolescents face risks during the extensive cortical reorganization of that stage. Regulatory frameworks, the authors argue, have lagged badly behind the science. Agencies such as the United States Food and Drug Administration and Environmental Protection Agency have restricted some compounds, and the European Union and World Health Organization have taken steps of their own, but critics contend these measures are insufficient. Most regulations still test chemicals one at a time and at high doses, missing the low-dose and mixture effects that define real-world exposure, and industry-conducted safety assessments raise conflicts of interest. The pattern of regrettable substitution is a case in point: when BPA was phased out, structurally similar analogs such as BPS and BPF moved in, potentially carrying comparable endocrine-disrupting activity. Legacy pollutants like DDT and PCBs continue to circulate decades after their bans.

What can be done? The review outlines a prevention agenda that spans individual action and structural reform. Reducing exposure means choosing products free of known xenoestrogens, improving manufacturing practices, and strengthening waste management. Public education can empower families, clinicians, and policymakers to make informed choices, while targeted interventions, including dietary modifications and environmental remediation, may help protect the most vulnerable. On the research frontier, the authors identify priorities that include characterizing emerging xenoestrogens, deploying sensitive tools such as neuroimaging and epigenetic profiling, testing whether pharmacological or nutritional therapies can mitigate harm, and untangling the synergistic effects of chemical mixtures. They also flag persistent methodological hurdles: non-monotonic dose responses that defy standard modeling, species differences that complicate extrapolation to humans, and the difficulty of sustaining longitudinal studies long enough to capture chronic and transgenerational outcomes. The bottom line, the authors conclude, is that safeguarding the neurological health of current and future generations demands a coordinated, precautionary response, one that combines rigorous independent research, evidence-based policymaking, international collaboration, and honest public engagement with the invisible chemical landscape that now surrounds every developing brain.

Subject of Research: Neurobehavioral and developmental toxicity caused by xenoestrogen endocrine-disrupting chemicals

Article Title: An overview of neurobehavioral and developmental toxicity induced by xenoestrogens

Article References: Shaw, R., Kamath, A. S., & Chaube, R. (2025). An overview of neurobehavioral and developmental toxicity induced by xenoestrogens. Discover Toxicology, 2(1), Article 10. https://doi.org/10.1007/s44339-025-00025-x

Image Credits: AI Generated

DOI: 10.1007/s44339-025-00025-x

Keywords: xenoestrogens, endocrine-disrupting chemicals, bisphenol A, phthalates, PCBs, estrogen receptors, neurodevelopment, epigenetics, developmental toxicity, neurobehavioral effects, brain development, public health