Carol Martin has strong expertise related to gender identity and expression, gender development, gender segregation and integration, and peer influence and relationships. Martin has been interested in gender since the beginning of her career, when she formulated (with Charles Halverson) a theory of gender development (i.e., Gender Schema Theory) that has become one of the most highly cited and heavily researched theories of gender development. For many years after receiving her doctorate, she tested the ideas proposed in the theory. She has written (with Diane Ruble) chapters outlining the state of the science of gender development for the "Handbook of Child Psychology." She was an associate editor for Developmental Psychology and has served on editorial boards of several journals. In the past 15 years or so, her work has turned toward the study of gender in peer relationships and academics.