- See also: Codex: Genetic Engineering.
Gene therapy is the insertion of genes into an individual's cells and tissues to alter the person's DNA. Gene therapy allows for the treatment of genetic disorders by replacing a defective mutant allele with a functional one using a carrier, also known as a vector, to deliver the therapeutic gene to the patient's target cells. Currently, the most common type of vectors are viruses that have been genetically altered to carry normal human DNA.
In the years before first contact, human genetic research was quite advanced, even allowing for the "uplifting" of animal species that lingered uneasily on the borders of sapience.
However, after making first contact with the turians and joining the Citadel, there were concerns that such modifications might lead to Earth's unique biodiversity being lost, so the Alliance Parliament passed the Sudham-Wolcott Genetic Heritage Act in 2161, leading to strict controls on genetic modification. As current law stands, modification of natural abilities is legal, but acquisition of new ones is not. For example, using gene therapy to increase muscle mass is legal, but adding the ability to digest cellulose is not.
Over time, human genetic research had developed to such an extent that basic genetic flaws could be corrected, either in utero or shortly after birth. For example, Ashley Williams received gene therapy for her maternal disposition to nearsightedness. Most human governments offer free assessment and correction therapies to its citizens, which has nearly eliminated genetic diseases from the human gene pool. All Alliance soldiers receive gene therapy -- provided by MarsGene -- upon enrolling, though most genetic therapies take years to come into their full effect.
The Citadel's own genetic restrictions allow for the creation of life for scientific or medical reasons, but forbid the creation of new sapient species. A few products have slipped past the regulations, most notably Sirta Foundation's medi-gel.
Commander Shepard can converse with Rafael Vargas and learn about Binary Helix's military enhancement packages in the guise of a buyer as part of Noveria: Espionage. Shepard can also discuss gene therapies with an arguing couple on the Presidium.