The below links answer the question for all you skeptics out there.. a great science experiment for kids, but a sobering message for parents.
Did you know that only 5–10% of all cancer cases can be attributed to genetic defects, whereas the remaining 90–95% have their roots in the environment and lifestyle."
Plants aren't just coated with pesticides.
"90% of lettuce tests positive for 47 different pesticides and 57 different chemical residues."http://www.pesticideinfo.org/DS.jsp?sk=13045
Plants soak up pesticides.
And no amount of washing is going to remove substances that are embedded in their tissues.