A group of French researchers headed by Jean-François Viel, MD, PhD, professor of epidemiology, Faculty of Medicine, Rennes, France, and the French National Institute of Health and Medical Research, investigated the associations between exposure to pyrethroid insecticides and behavioral skills in 6-year-olds..."We are being cautious because this is an observational study, so we cannot draw firm conclusions based simply on an association," he added. Nevertheless, "we think general practitioners should be aware of these findings."