BackgroundAmbient levels of pesticides (“pesticide drift”) are detectable at residences near agricultural field sites.ObjectiveOur goal was to evaluate the hypothesis that maternal residence near agricultural pesticide applications during key periods of gestation could be associated with the development of autism spectrum disorders (ASD) in children.MethodsWe identified 465 children with ASD born during 1996–1998 using the California Department of Developmental Services electronic files, and matched them by maternal date of last menstrual period to 6,975 live-born, normal-birth-weight, term infants as controls. We determined proximity to pesticide applications using California Department of Pesticide Regulation records refined using Department of Water Resources land use polygons. A staged analytic design applying a priori criteria to the results of conditional logistic regressions was employed to exclude associations likely due to multiple testing error.ResultsOf 249 unique hypotheses, four that described organochlorine pesticide applications—specifically those of dicofol and endosulfan—occurring during the period immediately before and concurrent with central nervous system embryogenesis (clinical weeks 1 through 8) met a priori criteria and were unlikely to be a result of multiple testing. Multivariate a posteriori models comparing children of mothers living within 500 m of field sites with the highest nonzero quartile of organochlorine poundage to those with mothers not living near field sites suggested an odds ratio for ASD of 6.1 (95% confidence interval, 2.4–15.3). ASD risk increased with the poundage of organochlorine applied and decreased with distance from field sites.ConclusionsThe association between residential proximity to organochlorine pesticide applications during gestation and ASD among children should be further studied.

Markers of higher estrogen exposure in the mother (age and parity) are associated with increased testicular cancer risk, and factors associated with fetal growth retardation may be associated with seminoma testicular cancer.

Most pesticides were not associated with elevated hypospadias risk. For the few that were associated, results should be interpreted with caution until replicated in other study populations.

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Two experiments investigated the acquisition, generalization, and extinction of the galvanic skin response (GSR) and digital vasomotor response to words under conditioned stimulus-unconditioned stimulus (CS-UCS) intervals of . 5, 5.5, 10.5, 15.5, and 20.5 sec. Experiment 1 used a forewarned reaction time situation with an innocuous tone as the imperative stimulus, whereas Experiment 2 used a noxious 110 dB white noise as the UCS. Differential conditioning of the GSR occurred under all intervals in both experiments. The most effective differential conditioning of the GSR appeared to occur with the short intervals, whereas the most effective conditioning of the vasomotor response appeared to occur under the longer intervals. Results from Experiment 1 clearly demonstrate that it is possible to study the acquisition of differential conditioning using an innocuous UCS. Similar results were obtained in Experiment 2.Comparisons between short and long CS-UCS intervals during extinction raise the problem of whether different kinds of responses are being compared under these two kinds of intervals. The short intervals may induce orienting reflexes in extinction due to the omission of the UCS from the CS-UCS stimulus complex. These responses are compared with anticipatory conditioned responses in the longer CS-UCS intervals that are uncontaminated by the omission of the UCS. In Experiment 2, the responses to the control words differed significantly as a function of CS-UCS interval, with the .5-sec interval producing the largest responses to the control words. Thus, a procedure is available for studying short and long CS-UCS intervals without the confounding of intervals with changes in the CS-UCS stimulus complex produced by test or extinction trials.