In the film Batman v Superman: Dawn of Justice (2016), Lex Luthor created a monster from General Zod's body and using his own blood.
What was the explanation of the procedure he used?
The movie shows Lex Luthor mixing his own blood with that of General Zod to create the monster in the Genesis Chamber of the Kryptonian spaceship that crashed in Man of Steel.
For those who skipped Man of Steel, the Genesis Chamber is used to create beings. By destroying the ship in Man of Steel, Superman (presumably) throws away any chance he had of creating more of his race.
Given the damage to that ship, it’s unclear how Doomsday is created. The Kryptonian science behind General Zod’s transformation goes largely unexplained in Batman v Superman.
The ship does say something before Luthor does the thing with the human blood. I took it to mean that Luthor in his 'genius' researched the history of Kryptonian cloning / species mixing experiments and discovered a list of prohibited projects, their outcomes, and the override (though it was pretty easy to override wasn't it?).
I don't remember exactly what the computer said.