Key findings

Using pesticides at home, having parents who work with pesticides (especially in farming), and living near farmland were the exposures most often linked to childhood leukemia and brain tumors.

The cancer risks were highest with pesticide exposure during pregnancy or early childhood, when children’s bodies and brains are still developing and more sensitive to harmful chemicals.

Studies found that children with these pesticide exposures were nearly twice as likely to develop cancer, and in some cases more than three times as likely, depending on the type, timing, and amount of exposure.

When Yesica Ramírez was pregnant, she spent her days mixing pesticides in giant vats at a Florida ornamental plant nursery. She wasn’t given a mask or gloves and couldn’t afford her own protective gear. Even as rashes spread across her arms and hands, she pulled her shirt over her mouth to avoid inhaling fumes. 

“As a farm worker, you make a very low salary, and it’s either buy protective equipment or you feed your family,” said Ramirez. “I chose to feed my family.”

At the time, she said, chemical exposures at her workplace were rarely discussed. It wasn’t until a coworker discovered a manual describing pesticide hazards and the safety measures her employer should have followed that she realized the risks.

Months later, her daughter was born with craniosynostosis, a condition in which the bones of an infant’s skull fuse too early. The baby also developed eczema and sleep apnea.

For years, Ramirez has suspected that the pesticides she handled during pregnancy contributed to her daughter’s health problems. Her concerns echo findings from numerous studies that point to pesticide exposures during pregnancy and childhood as a risk factor for childhood cancers — and from a recent review that highlights decades of evidence linking pesticide exposure specifically to childhood leukemia and brain cancer.

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Critical windows of cancer risk: pregnancy and early childhood 

Published last month [May 2026] in the International Journal of Cancer, University of Nebraska-Lincoln researchers analyzed findings from 88 epidemiological studies spanning more than 40 years. Heavily agricultural states such as Nebraska and Iowa have among the highest rates of pediatric cancer in the U.S., though pesticides are detected throughout the country in both rural and urban areas. 

The strongest and most consistent associations between pesticides and pediatric cancer across studies emerged during pregnancy and early childhood. Cancer risks — particularly for acute lymphoblastic leukemia (ALL), a fast-growing blood cancer — ranged from roughly 1.5 times to more than three times higher, depending on the timing and type of exposure. 

“Overall, exposure to both occupational and household pesticides is significantly associated with increased risks of leukemia and brain cancer in children, and risk for specific cancer types appears to be related to parental exposure during the prenatal period,” the authors wrote.

Decades of research link pesticides to childhood cancer

The review underscores growing evidence linking childhood cancers to environmental pollution. It also comes amid legal and regulatory scrutiny of pesticide health risks, including litigation involving major manufacturers such as Bayer (and its subsidiary Monsanto) and Syngenta.

“It adds to an abundance of literature identifying pesticides exposures during pregnancy and childhood as a risk factor for childhood cancers,” said Dr. Mark Miller, an associate professor at UCSF who directs the Childhood Cancer and the Environment Program (CCEP) for the National Pediatric Environmental Health Specialty Unit (PEHSU) network. “Reducing children’s exposure to pesticides will help to prevent cases of childhood cancers.”

Although pesticide residues occur in food and drinking water, the review focuses on exposure from agricultural drift, workplace exposure, and pesticide use in and around homes. Children often come in contact with residues carried home on parents’ clothing and through contaminated household dust. Flea-and-tick treatments for pets also expose them to pesticides.

The authors said the evidence now justifies preventive action to reduce exposures.

“Residential or agricultural pesticide use in spaces where children spend most of their time poses a significant risk to their well-being and physical development,” they wrote.

Prenatal pesticide exposure may worsen survival outlook

Leukemia is the most common childhood cancer, while brain tumors are the leading cause of cancer-related death in children. ALL accounts for about three-quarters of childhood leukemia cases.

Children are especially vulnerable to toxic chemicals because their brains and organs are still developing. Their bodies are also less able to process and remove contaminants. Some pesticides can cross the placenta into the fetus, meaning exposure may begin before birth.

A 2025 study of more than 800 children with ALL found that those exposed to residential pesticides during pregnancy had a 60% higher risk of death within five years of diagnosis. Prenatal exposure to rodenticides, mainly used to kill rats and mice, increased the risk by 91%.

“This study highlights that exposures in the home environment, even before a child is born, may have lasting effects on survival after a leukemia diagnosis,” said co-author Dr. Lena Winestone, a pediatric hematologist-oncologist at UCSF Benioff Children’s Hospitals.

Household pesticide use repeatedly linked to childhood cancers

Studies consistently identified household pesticide exposure as a risk factor for leukemia and brain tumors. Prenatal exposure appeared more strongly associated with risk than exposure later in childhood.

Examples from the review include:

Higher leukemia rates among children exposed to repeated professional pest control treatments before birth and during early childhood

Increased brain tumor risk among children whose mothers handled flea-and-tick pet products during pregnancy

Roughly doubled brain tumor risk among those whose fathers applied herbicides for lawn or garden care, with lower risks if they changed clothes or washed afterward

A large meta-analysis also found elevated leukemia risk among mothers exposed to pesticides during pregnancy, especially insecticides. Risk increased when both parents were exposed. 

Another study found a more than fourfold increase in high-­grade glioma (a fast-growing brain cancer) risk when pest-control treatments occurred during pregnancy. 

Living and working near farmland increases pediatric cancer risks

Several studies reported that children in highly agricultural regions had two to three times the leukemia risk of those in less intensive farming areas. Herbicides and insecticides showed the strongest associations with leukemia, while all major pesticide classes were linked to brain cancer. 

Parental occupational exposure also emerged as a risk factor. One study found children of pesticide applicators who did not wear gloves faced nearly double the cancer risk.

The review highlighted studies showing:

Another California study linked prenatal exposure to several pesticides sprayed near homes to higher risks of ALL and acute myeloid leukemia (AML). Among the pesticides associated with elevated risk was the weedkiller diuron, which remains under EPA review. 

Researchers suspect some children are genetically more vulnerable to pesticide-related cancers than others. Several studies linked pesticide exposure to genes involved in chemical detoxification and DNA repair.

One small study found higher leukemia risk among children whose mothers were exposed to pesticides during pregnancy and carried genetic variants involved in processing carcinogens. Risks also increased among children with those traits who were exposed to indoor insecticides.

The researchers said pesticides may cause direct DNA damage or alter gene expression through epigenetic changes (alterations in how genes are expressed). They also raised concerns that pesticide-related genetic damage could accumulate across farming communities from one generation to the next.

“Across generations, exposure to pesticides can lead to alterations in DNA,” they wrote.  “As a family progresses through subsequent generations, the cumulative damage from several generations becomes apparent.”

Drinking water and chemical mixtures add to cancer concerns

Few studies examined drinking water exposure directly. In farming regions, nitrates from fertilizer runoff and animal manure often co-occur with pesticides in groundwater, rivers, and streams. Some research suggests combined exposures may pose greater risks than individual pesticides, such as glyphosate, chlorothalonil, and paraquat, recently banned by Vermont.

A Maryland study found significantly higher childhood cancer rates where groundwater contained nitrate alongside herbicides such as atrazine. A Nebraska study similarly linked pesticide mixtures to higher rates of childhood cancers, including leukemia and brain tumors.

“The findings highlight the importance of evaluating agrochemicals, both individually and in mixtures, in drinking water as potential risk factors for cancer development in children,” the authors wrote.

Studies reveal gaps in pesticide monitoring, cancer research

The researchers noted that many studies relied on indirect measures of exposure, such as proximity to farmland, instead of direct chemical testing. Data on private wells, long-term exposure histories, and household water treatment practices also remain limited.

Still, they said the evidence across studies was sufficient to justify more research and stronger prevention efforts. If she had her wish, Ramírez, who now works as general coordinator of the Farm Worker Association of Florida, says she’d prefer to turn back the clock.

“The best thing to do is to go back to the way things used to be — to grow plants without using all these chemicals and to grow things organically,” she said. “But where we are now, we’re far away from that.”

Reference

VanDeSteeg GN, Russum AR, Sandbulte MR, Rogan EG, Rhoades MG. Environmental pesticide exposure in the etiology of pediatric brain tumors and leukemia: a scoping review of epidemiological studies. International Journal of Cancer. Published online May 26, 2026. doi:10.1002/ijc.70546