Gene therapy is a type of medical treatment that involves introducing new genetic material into a person's cells to help fight or prevent disease. It can be used to replace, remove, or repair faulty genes responsible for inherited diseases or those caused by mutations in an individual’s DNA. The goal of gene therapy is to cure or alleviate the symptoms of genetic disorders and it has shown promising results in treating conditions such as cancer, immune deficiencies, and certain hereditary diseases. Gene therapy involves several techniques including viral vectors, which are modified viruses that carry healthy genes to target cells; CRISPR-Cas9 gene editing technology, which allows for precise changes in DNA sequences; and stem cell transplantation, where new genetic material is introduced into reprogrammed adult stem cells. Overall, gene therapy holds great potential as a groundbreaking approach to treating diseases at their source by targeting the root cause of illnesses caused by faulty genes or mutations.