The Son of Bizarro! was a three-part Superman story appearing in Superman # 140. Parts 2 and three of the story, appearing in the same issue, were called The Orphan Bizarro! and The Supergirl Bizarro!.
Part I - The Son of Bizarro
On Htrae, Bizarro constructs his Fourtriss uv Bizarro, a Bizarro version of the Fortress of Solitude. After completing the structure, he discovers that his wife, Bizarro Lois Lane, has had a baby. However, the baby is "ugly", resembling a Human child rather than a Bizarro. The child also displays his father's superpowers. However, the other Bizarros are disgusted by his appearance and reject him. Bizarro and Bizarro Lois Lane both love their son, and keep him hidden from the world.
When his plan fails and the baby reveals himself, Bizarro and Bizarro Lois plan to take the baby to another world and live there with him. Bizarro flies up to find a world, sees a strange artificial sattelite, leaves the baby inside temporarily while he returns to Htrae to rescue Bizarro Lois. The sattelite, meanwhile, the sattelite returns to Earth with the baby inside.
On Earth, the baby is found by a passing couple, who take him to the Midvale Orphanage.
Part II - The Orphan Bizarro
Linda Lee, alias Supergirl, is left in charge of the new baby, which has been dubbed Baby Buster by the orphanage staff. She quickly discovers the baby's super-powers. However, the baby escapes from her and she chases him to Metropolis. There, Superman sees the baby and helps Supergirl catch him. She then relates the story.
Superman decides the baby should stay at the orphanage for the time being, under Linda's watchful eye. Begrudgingly, Supergirl agrees, and takes care of him. Soon after, Superman arranges to move him to the Fortress of Solitude, where he can play with Krypto. Superman and Supergirl will raise him.
Meanwhile, Bizarro watches the situation with his telescopic vision and cries at the sight of his son accepting Superman and Supergirl as parents, but accepts it as it's the only way for his son to live a peaceful life. Back at the fortress, Supergirl begins to do some chemistry homework assigned to Linda Lee while Baby Buster sleeps. She uses her X-Ray Vision to save time, causing an explosion. The explosion makes Baby Buster resemble a Bizarro, much to her and Krypto's horror.
Part III - The Supergirl Bizarro
Superman returns to the fortress to see the Bizarro baby and the Bizarro Supergirl. Realizing that the Baby's actually the son of Bizarro and Bizarro-Lois after overhearing the baby say so, he orders Bizarro Supergirl to take the baby and return to Htrae. But Bizarro Supergirl refuses, having already fallen in love with the child. Superman tries and fails to forcibly remove him from her arms.
Bizarro, meanwhile, spies the situation and, seeing his baby looking like a Bizarro, flies to Earth to retrieve him. Also failing to pry the baby from Bizarro Supergirl's arms, he accuses Superman of creating Bizarro Supergirl on purpose, to be a foster mother to Baby Buster. Superman denies this, but Bizarro doesn't listen and returns to Htrae, declaring war on Superman.
Superman and Supergirl prepare for the oncoming Bizarro invasion. Superman dons his Lead Suit and uses the Duplicator Ray on some Kryptonite, creating a pile of Blue Kryptonite, which harms Bizarros. He thus paralyzes the oncoming Bizarros, and the Bizarro army retreats.
Superman brings a piece of blue Kryptonite back with him to Earth where he uses it on Bizarro Supergirl. He and Supergirl then take the baby and fly to Htrae, with Bizarro Supergirl in persuit. They return the baby to his parents, and Bizarro thanks Superman and calls off the war, realizing that it was Bizarro Supergirl who was the cause of the trouble.
Superman then looks around and sees other Bizarro parents with humanlike children. He realizes that Bizarros are born looking like Humans and then metamorphose into a more Bizarrolike form. This is part of their natural development. Superman and Supergirl return to Earth, on their way seeing that Bizarro Supergirl has killed herself by blundering into some leftover Blue Kryptonite.