Sexual development (clinical endocrinology) is the biological process of sex differentiation and maturation of the reproductive system and secondary sexual characteristics, primarily regulated by the intricate interplay of hormones produced by the endocrine glands. This field investigates the complex hormonal axes and signaling pathways that govern prenatal sex determination, pubertal development, and reproductive function throughout the lifespan. In clinical endocrinology, this concept is central to understanding typical development and diagnosing and managing conditions arising from disruptions in these processes, including disorders of sex development (DSD), pubertal timing abnormalities, and other endocrine-related reproductive health issues.