Genetronics was a field of science that dealt with patterning energy into matter, duplicating the highly ordered genetic patterns inherent to a lifeform's cell processes.
In 2368, Doctor Beverly Crusher reminded Dr. Toby Russell that they'd already discussed and dismissed the possibility of a genetronic solution to Worf's paralysis. According to Starfleet Medical, Russell had already been denied the chance to test genetronics on humanoids three times previous. (TNG: "Ethics")