The Lancet, a leading medical journal, published in October 2015 the answer to a question that has been on the minds of people all over the world: Does anesthesia affect the mental development of infants and young children, and if so, which is better? If so, which is better: general anesthesia or local anesthesia? This multinational, multicenter study from 28 hospitals in 7 countries around the world answers this question well. In this international, evaluator-blinded, randomized, controlled, equivalence trial, researchers recruited infants born at more than 26 gestational weeks and less than 60 gestational weeks who had undergone inguinal hernia repair from 28 hospitals in Australia, Italy, the U.S., the U.K., Canada, the Netherlands, and New Zealand. These infants were randomly assigned (1:1) to receive awake local anesthesia or sevoflurane-based general anesthesia. Web-based randomization of two or four blocks was completed and stratified by place of birth and gestational age. These infants were excluded if they had risk factors for neurologic injury. The primary outcome of the study will be full-scale IQ scores on the Wechsler Preschooler Intelligence Scale, Third Edition (WPPSI-III) at age 5 years. The secondary outcome will be the Bailey Scales of Infant and Toddler Development III Composite Cognitive Score assessed at age 2 years. The analysis was adjusted for gestational age at birth for each protocol. A mean difference of five points (1/3 SD) was predefined as the clinical equivalence boundary. Between February 9, 2007, and January 31, 2013, 363 infants received awake local anesthesia and 359 infants received general anesthesia. Outcome data were available for 238 infants in the awake local anesthesia and 294 infants in the general anesthesia group. In analyses according to each protocol, the cognitive composite score (mean [SD]) was 98.6 (14.2) for the awake local anesthesia group and 98.2 (14.7) for the general anesthesia group. Mean values were equal between groups (0.169 for awake local anesthesia minus general anesthesia and 2.30?2.64 for 95% Cl). The median time in the general anesthesia group was 54 minutes. For this secondary outcome, the researchers found no evidence that sevoflurane anesthesia, which takes less than 1 hour in infancy compared with local anesthesia, increases the risk of adverse neurodevelopmental outcomes at 2 years of age.