Behavior genetics is a field that studies how our genes and environment contribute to differences in behavior and traits among individuals. Traditionally, twin studies have long been a cornerstone of this field, helping researchers understand how genetics influence behavior. Recently, the focus has expanded to include studies with more complex family structures, e.g., children of twins (CoT, D'Onofrio et al., 2003) and mother-daughter-aunt-niece (MDAN, Rodgers, Bard, Johnson, D 'Onofrio, & Miller, 2008). These broader studies offer more detailed insights into how our genes and environment shape us, but they also make analyzing and organizing the data more complex. BGmisc simplifies the analysis of these complex data structures by offering a comprehensive suite of functions for accommodating families of any size, from twins to extensive pedigrees.