Insecticides are part of our lives. These substances are routinely used to kill, repel or control animals and plants that are considered to be pests, from mosquitos and mites to dandelions and poison ivy.

The problem is insecticides affect more than just bugs and annoying plants. They not only kill pests in our homes, gardens and lawns — and are sprayed on the food we eat — they're also contributing to a dramatic decline in sperm count, a meta-analysis of more than two dozen studies has found.

“Over the course of 50 years, sperm concentration has fallen about 50 percent around the world,” senior author Melissa Perry, dean of the college of Public Health at George Mason University, said in a press release.

Be aware of those non-organic fruits and vegetables that have the high levels of pesticides such as strawberries, bell peppers, peaches and pears, blueberries, cherries, spinach and lettuce.

The researchers looked at 25 studies from around the world on insecticides made up of organophosphates and N-methyl carbamates and saw a connection with declining sperm count.

“Understanding how insecticides affect sperm concentration in humans is critical given their ubiquity in the environment and documented reproductive hazards. Insecticides are a concern for public health and all men who are exposed primarily through the consumption of contaminated food and water,” Lauren Ellis, a member of the team of researchers and a doctoral student at Northeastern University, said in a press release.

The research team came to this conclusion after systematically reviewing decades of human evidence. They found that men who were more highly exposed to the insecticides — such as those who work in agriculture — had significantly less sperm concentration than men who had the least exposure.

The findings support the need for a warning about the sperm-killing effect of insecticides. “This review is the most comprehensive study to date, sizing up more than 25 years of research on male fertility and reproductive health. The evidence available has reached a point that we must take regulatory action to reduce insecticide exposure,” Perry said.

Until that happens, how can we avoid being exposed to these dangerous chemicals? Experts suggest:

  • Buying organic and locally-grown fruits and vegetables which are likely to be treated with fewer pesticides.
  • Washing fruits and veggies before eating and peeling skins when possible.
  • Being aware of those non-organic fruits and vegetables that have the high levels of pesticides such as strawberries, bell peppers, peaches and pears, blueberries, cherries, spinach and lettuce.
  • If you garden, research the use of non-toxic ways to control pests. Some techniques include introducing beneficial insects, planting garlic and crop rotation.
  • Have a no-shoes policy in your home to avoid tracking pesticides in from outside.

Insecticides aren't the only reason sperm count is on the decline. Other factors found to bring down sperm count include: obesity, poor diet, chronic disease and exposure to additional environmental toxins including pollution and BPA and PFAS — bisphenol A and per- and polyfluorinated substances respectively — found in cleaning products, nonstick cookware and personal care products.

The study is published in Environmental Health Perspectives.