Human genetics is a rapidly developing branch of biological and medical science that studies heredity, variation, and the mechanisms of genetic transmission in humans. The study of human genetics plays a crucial role in understanding how genetic information is stored, transmitted, and expressed in the human body. This article provides a detailed overview of the structure and function of genetic material, including DNA, genes, and chromosomes, as well as the biological principles underlying inheritance. Special attention is given to the role of genetic mutations, gene interactions, and chromosomal abnormalities in the development of hereditary diseases. The integration of molecular genetics into clinical practice has significantly improved the diagnosis, prevention, and treatment of genetic disorders. Furthermore, this work highlights the importance of genetics in modern medicine, particularly in the field of personalized medicine, where treatment strategies are tailored according to an individual's genetic profile.