We take the opportunity of the 35th anniversary of Sex Roles to examine the journal and the field of gender research from a biological perspective. We discuss the limited coverage of biological perspectives in the pages of the journal and likely reasons for it in light of historical perspectives on the role of biology in gendered psychological processes and behaviors, review briefly contemporary research on biological (especially hormonal) influences on gender-related behavior, advocate for greater attention to biological perspectives, and suggest ways to integrate biological and socialization approaches into questions of interest to gender researchers.In honor of the journal's 35th anniversary, the editors of Sex Roles are publishing a special series of articles (Frieze and Dittrich 2010). In our paper in this series, we consider the impact of biological factors on gender-related behavior and psychological processes. We are primarily concerned with characteristics that differ in level or form between boys or men and girls or women, most of which also show variations within each gender; we do not address social and political factors that disproportionately affect women's lives (such as sexual harassment or rape). Our domain of focus is usually referred to as gender differences, gender typing, gender-related behavior, or gendered characteristics (e.g., Ruble et al. 2006). We use this paper to consider historical and contemporary work on the biology of sex and gender, examine how these issues have been represented in Sex Roles, speculate about why biological research has not played a larger role than it has, and, finally, suggest some changes to the journal's mission.Why should gender researchers consider the possibility that genes and physiology (such as hormones and brain function) are important for behavior? Sex Roles has consistently been focused on social processes, stereotyping, and experiences of particular relevance to women's lives; this is the stated mission of the journal. But, increasingly, behavior of all types has been shown to be influenced by genes and physiology and mediated by the brain. A complete picture of gender-related behavior necessitates a consideration of biology.