This document provides an introduction to concepts related to gender identity, gender expression, and biological sex. It defines these terms and discusses their differences. It also addresses the prevalence of intersex individuals, myths and misconceptions, and theoretical considerations for counselors. Gender identity refers to one's internal gender, gender expression is one's outward presentation, and biological sex refers to physical characteristics. These do not always align. The document aims to educate on this topic which is important for multicultural counseling.