An experimental medical device that reads a patient's genetic code and grows a complete replacement organ, used to give Worf a new spinal column.
The genetronic replicator appears in the episode Ethics. A falling cargo container crushes Worf's spine and leaves him paralysed. By Klingon custom he should now end his life, and he asks Riker to help him do so.
Doctor Toby Russell, a visiting neurogeneticist, proposes her untested invention instead. It would scan Worf's DNA and replicate an entire new spinal cord to be transplanted in place of the old one. Doctor Crusher objects strongly, since the technique has never been tried on a humanoid and Russell has a record of taking chances with patients.
Worf chooses the operation. The transplant succeeds but he dies on the table, and revives only because Klingon anatomy carries back-up systems. Crusher tells Russell plainly what she thinks of her methods.