 In the season 8 episode "Bloodline", it's revealed that Zod's desire for a child leads to the creation of "The Beast" aka Doomsday.Years later in the failing years of Krypton, the now General Zod and his wife, Faora, were unable to have children due to infertility on Faora's part, and so they began collecting the DNA of the most violent alien species on Krypton and fused them together with their own DNA to create their own perfect "son".They sent him as genetic samples to Earth attached to Kal-El's ship where the son of Zod is given the name of "Davis Bloome".