Herbicides, GM crops and autism

May 2019

Indications of links between the world's most used, GM-friendly herbicide, glyphosate, and premature death from cancer and Parkinson's disease raise concerns about what we may be inflicting on ourselves in the longer term [1,2].

Do glyphosate-based-herbicides only make their toxic presence felt as we approach old age? What are the chances they cause us damage in the womb and in infancy too?

Many pesticides, including glyphosate, are known to have neurotoxic effects, and increasingly scientific evidence is implicating ambient pesticides as a risk factor for autism spectrum disorder.

Although autism was previously considered rare, recent prevalence estimates range from 1.7% to 2.6% of children in the developed world. Statistics are uncertain because 'autism' covers a spectrum of conditions which are complex and heterogeous, ranging from mild development disorders to intellectual disability.

It's a tough issue to investigate. However, researchers in California have made a start by carrying out an epidemiological survey in the state's Central Valley, a large, heavily agricultural area.

Armed with data from California's mandatory 'Pesticide Use Reporting Scheme', the scientists investigated the incidence of autism (excluding milder forms), and the incidence of autism with intellectual disability within two kilometres of pesticide use.

They identified nearly 3,000 patients with autistic spectrum disorder, about 15 percent of which had accompanying intellectual disability.

This revealed a 'small to moderate' increased risk of the disorder after exposure to several pesticides, including glyphosate, dicamba and 2,4-D. All three of these chemicals are used on herbicide-tolerant GM crops, and all three have prior experimental evidence of neurotoxicity. The association was strongest in individuals with accompanying intellectual disability.

How these findings could translate into public health actions isn't obvious because "reducing maternal exposure to zero for a pesticide such as glyphosate might be close to impossible in some populations".


The very idea of 'conventional' agriculture without chemicals, especially glyphosate, is clearly unthinkable, no matter how many people are damaged by them. 

There's never been a stronger case for going organic and GM-free because GM crops without associated agrichemicals (including insecticides made by the GM plants themselves) don't exist.



Note. Genetic susceptibility is also a major risk factor in autism, but isn't the whole story.

  • Amanda V. Bakian and James A. VanDerslice, March 2019, Pesticides and autism, BMJ
  • Ondine S. von Ehrenstein, et al., February 2019, Prenatal and infant exposure to ambient pesticides and autism spectrum disorder in children: population based case-control study, BMJ
  • Early exposure to pesticides - including glyphosate - linked to increased risk of autism, GM Watch 21.03.19
  • Jonathan Hettinger, Volatile pesticide to be sprayed on soybeans and cotton this season,, 26.03.19

    Photo Creative Commons

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