Sometimes called "gene therapy," medical gene transfer involves adding or modifying genes in a person's cells (other than those found in his or her sperm or eggs). The "new" genes are intended to function in ways that would alleviate a medical condition. They would not be passed on to any future generations.
Gene transfer may eventually become an effective treatment for some important medical conditions. Clinical trials have been underway since 1990, but so far have been mostly unsuccessful, involved several conflict-of-interest scandals, and produced adverse results including deaths.
Gene transfer has also been proposed for "enhancement" purposes. This application could raise troubling social and ethical questions.