"Human studies": In multiple epidemiological studies, chlorpyrifos exposure during gestation or childhood has been linked with lower birth weight and neurological changes such as slower motor development and attention problems. Children with prenatal exposures to chlorpyrifos have been shown to have lower IQs. They have also been shown to have a higher chance of developing autism, attention deficit problems, and developmental disorders. A cohort of 7-year-old children were studied for neurological damages from prenatal exposure to chlorpyrifos. The study determined that the exposed children had deficits in working memory and full scale intelligence quotient (IQ). In a study on groups of Chinese infants, those exposed to chlorpyrifos showed significant decreases in motor functions such as reflexes, locomotion, and grasping at 9 months compared to those not exposed. Exposure to organophosphate pesticides in general has been increasingly associated with changes in children's cognitive, behavioral and motor performance. Infant girls were shown to be more susceptible to harmful effects from organophosphate insecticides than infant boys.