The question from students and some educators usually sounds like this: "How can we have so much variation in gender if, biologically speaking, we only have two sexes?" Given the vast diversity of human sexual and reproductive anatomy (SRA), it is staggering how little we, as a society, know about it. There are many reasons for this unfamiliarity, including the secrecy surrounding the medical treatment of people with atypical SRA, the general discomfort with any departure from the binary sex model (male or female), and the amalgamation of sexual anatomy with gender. The aim of this article is to introduce and describe differences of sex development from the biological, medical, and social standpoint and to offer general recommendations and resources for a respectful and inclusive school psychology practice with this student population, their families, and school communities.