
Cloning technology has been a much conjectured as a future reality since the atomic age began. On parallel planets, themselves known for producing near identical doppelgängers on each world, this has become a reality. Case in point, the business-suit busybody boys Jimmy Olsen and Johnny Thunder, friends of Superman!
On Earth-One, photo-journalist Jimmy Olsen of the Daily Planet had hundreds of stories he pursued which led him into a myriad of zany adventures over the years. Moreso than his Earth-Two counterpart on Earth-Two who was employed with the Daily Star, this Jimmy frequently employed the aid of his best friend Superman, whom he summoned whenever in need with his emergency signal watch which broadcast a high-pitch frequency only his friend could hear and from time-to-time adopted the stretchy alter ego of Elastic Lad.
On Earth-Two, amateur adventurer Johnny Thunder had hundreds of wacky tales he was involved with throughout the decades. While his Earth-One counterpart was busy leading his Lawless League gang, this Johnny was the first new recruit of the Justice Society of America, whom he shared several adventures with. During most of his fanatical forays, Johnny employed the aid of his stretchy Thunderbolt, whose powers protected Thunder from various threats and whom he could summon by saying the phrase Cei-U (or "Say You").
On occasion, both young men encountered multiple copies of themselves. Jimmy met his clones created in Project Cadmus, who were tasked as guards of the government facility. Johnny spawned his own clones whom he unleashed upon the Black Dragon Society of Imperial Japan who were attacking America.
Of course, there were several other clones developed by various intellectuals for a variety of purposes, some for the betterment of man and some for ill-gotten gains. Some of these were:
- Supergirl's miniature clones merged to become Linda Danvers II, Power Girl's cloned cells extended her life and youth
- Clones of Manhunter agents Paul "Manhunter" Kirk and Molly "Harlequin" Mayne spawned to dominate their Earths.
- T.O. Morrow and Per Degaton's temporal clones whom they used as agents against the Justice League and Justice Society.
- Sinestro's clones whom he used as pawns of both Earths versus the Green Lanterns arch-foe Hal Jordan and new foe Alan Scott.
- Solomon Grundy and his various clones on Earths One and Two.
- Bizarro and Funny Face clones of heroes and villains who bedevils the Supermen of twin Earths Kal-El and Kal-L.
- Clones of Justice League & Justice Society members who had short-lived costumed careers of their own.



























