Introduction According to ecological and sociocultural models, societies’ values regarding gender roles shape parenting practices, including the ways parents talk to their girls and boys (Leaper & Friedman, 2007). US parents likely exercise gendered socialization practices via language use e.g., socializing masculine-stereotyped attributes by talking more about causation and cognition with boys, but feminine-stereotyped attributes by talking more about emotion and physical states with girls. Alternatively, evidence of diminished gender divisions (Tamis-LeMonda& McFadden, 2010), indicate that parents may exercise more gender-neutral socialization practices (talking similarly about causation, cognition, and emotion to boys and girls) or cross-gendered socialization practices (talking more about emotion with boys than girls, etc.). Research on parents’ socialization via communicationwith children has focused on preschoolers and /adolescents (e.g., Tenenbaum& Leaper, 2003); little is known about US parents’ socialization via communication with infants and toddlers. (2) Do the frequencies of US mothers’ mental state talk about cognition, causation, desire, emotion, and physical states vary according to child gender at ages 12 and 30 months? (2) Does mothers’ gender-based emotion socialization via communication vary according to child-age? Research Questions Methods The present sample was drawn from an on-going longitudinal study on the relations between young children’s emotional development and caregivers’ expression, representation, and understanding of emotions. 46 US mothers participated when children were 12 and 30 months old (25 girls). Procedure: Mothers were given two story stems and asked to tell the children two open-ended stories. Coding: We coded each instance of the mothers’ mental-state talk into the following categories: (1)Cognition(e.g., think and know) (2)Causal Talk(e.g., because and if) (3)Desires(e.g., want and like) (4)Emotion(e.g., sad and happy) (5)Physical State (e.g., sleepy and hungry) Findings US mothers exercise gender-neutral socialization practices—talking similarly about causation, cognition, desires, emotions, and physical states to boys and girls in infancy and toddlerhood. Mothers talked more about causation and emotion and less about physical states and desires when children were 30-months compared to 12-months. For both genders, mothers talked less about emotions than causation, desires, and cognition at 12-months than at 30 months. For both genders, at 30 months physical states were less frequent, and the difference between the frequencies of desire and emotion disappeared at 30 months. Discussion As boys and girls grow from infancy to toddlerhood, US mothers place greater emphasis on socializing both masculine-stereotyped attributes (e.g., shifting from talking equally about physical states, cognition, and causation at 12 months old, to talking more about cognition and causation than physical states at 30 months old) and feminine-stereotyped attributes (e.g., talking more about emotion when children were 30-month-old than 12-month-old). The indications of gender-neutral socialization practices and the importance of socializing both masculine-and feminine-stereotyped attributes may reflect diminished gender roles in contemporary US society (Tamis-LeMonda& McFadden, 2010)FONDECYTFONDECYT