Time -- Moms-to-be have a lot to worry about while they’re expecting, especially since everything they’re exposed to has a chance of affecting their developing baby. And that includes pesticides, from the kind that farmers spray on fruit and vegetable crops to the bug-killers that we use in our homes. In three separate studies published in the journal Environmental Health Perspectives, researchers document that a mother’s prenatal exposure to these chemicals can affect the cognitive development of her child, in some cases up to nine years later.