We improve the breed by sticking ourselves full o’ junk – personality modifications, physical improvements, etc. etc. Or maybe we use drugs or genes instead. See also “Human Evolution.” Body modification is also one of the recurring themes in the biopunk sub genre.
"Scanners Live in Vain," Cordwainer Smith
The Six Million Dollar Man (TV)
(ETA: A friendly Anonymous commenter has reminded me that this show was based on Martin Caidin's 1972 novel, Cyborg. Thank you, Anonymous Commenter!)
Blood Music, Greg Bear
“Flowers for Algernon,” Daniel Keyes
When Gravity Fails, George Alec Effinger