The National Institutes of Health recently published a statement requiring sex as a biological variable in studies. This is in part simply because it's good science, and in part to correct for decades in which both animal and human studies were largely conducted with male subjects. In their review paper responding to this statement, Dr. Tracy Bale and Dr. Neill Epperson discuss how sex has a direct impact on brain development, and how it results in a sexually dimorphic brain: meaning there are physical differences between males and females. Listen to the latest BrainPod, Neuropsychopharmacology's official podcast, to hear Dr. Bale and Dr. Epperson discuss this topic!