A new study reveals greater evidence that common pesticides may be a factor in a child being diagnosed with autism or developmental delay.

In a large study, researchers at UC Davis MIND Institute examined how gestational exposure may induce "developmental neurotoxicity in humans," which has been associated with developmental delay and autism spectrum disorders (ASD).

"This study of ASD strengthens the evidence linking neurodevelopmental disorders with gestational pesticide exposures, and particularly, organophosphates, and provides novel results of ASD and DD associations with, respectively, pyrethroids and carbamates," states the study's conclusions.

The report claims women living close to farms and areas where chemical pesticides were used face a two-thirds increased risk of having a child diagnosed with ASD or DD. If the exposure occurs during the second and third trimesters the association is even stronger, claims the research.

The study, published by Environmental Health Perspectives, suggests pregnant women in these specific locales need to take special care to avoid interaction with agricultural chemicals.

"This study validates the results of earlier research that has reported associations between having a child with autism and prenatal exposure to agricultural chemicals in California," said lead study author Janie F. Shelton, a UC Davis graduate student who now consults with the United Nations.

The study was conducted in California, the top agricultural state in the country, and examined pesticide use data and residential data regarding ASD diagnosis.

"Ours is the third study to specifically link autism spectrum disorders to pesticide exposure, whereas more papers have demonstrated links with developmental delay," said Shelton, noting more research is required.

Earlier this month, TechTimes reported on another study regarding autism which revealed boys with autism are more likely to have been exposed to higher hormone levels in the womb than those who develop normally.

University of Cambridge and Statens Serum Institute scientists analyzed the hormone levels of almost 20,000 samples and compared the samples from 128 boys with autism with samples from 217 boys without it. The girls were excluded because only a few had autism and other issues made it hard to compare levels of steroid hormones between girls with autism and girls developing normally.

The study findings may help researchers discover some of the main causes of autism and figure out why males are four or five times more at risk to be diagnosed with autism, which affects about 1 percent of the human population.

"In the womb, boys produce about twice as much testosterone as girls, but compared with typical boys, the autism group has even higher levels. It's a significant difference and may have a large effect on brain development," director Simon Baron-Cohen of the Autism Research Centre at Cambridge University said.

Dr. Michael Lombardo, Baron-Cohen in Cambridge, and Professor Bent Norgaard-Pedersen in Denmark and their team warn that while the new study may aid in explaining why autism is more common in boys than girls, people should not use testosterone levels to screen for the condition.

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