There is increasing evidence that early life exposures may influence future health outcomes although there is a critical need to more fully understand how these may differ from exposures received later in life. The farm environment includes pesticides that have been suggested to increase cancer risk in both children and adults. A review of the literature identified crucial gaps in our knowledge and highlighted the need for accurate exposure assessment, including separate parental interviews, specific pesticide exposure questions, and semiquantitative exposure measures that can be used to confirm information obtained through questionnaires 2. Some studies suggest that the timing of exposure may be particularly important. For example, in a study of the insecticide DDT and breast cancer, researchers observed the highest risks among women exposed prior to age 14 compared to later in life 3. The agricultural environment also includes other exposures such as animals, allergens, and endotoxins. These exposures may influence immune function, particularly when exposed at a young age, and subsequently affect later cancer risk.