The U.S. Centers for Disease Control reports that one of the main sources of pesticide exposure for U.S. children comes from the food they eat.

According to the Food and Drug Administration, half of produce currently tested in grocery stores contains measurable residues of pesticides. Laboratory tests of eight industry-leader baby foods reveal the presence of 16 pesticides, including three carcinogens.

According to EPA's "Guidelines for Carcinogen Risk Assessment," children receive 50% of their lifetime cancer risks in the first two years of life.

In blood samples of children aged 2 to 4, concentrations of pesticide residues are six times higher in children eating conventionally farmed fruits and vegetables compared with those eating organic food.

(Sources and more facts here: http://www.organicconsumers.org/organic/wic-faq.pdf)