The Lone Kryptonian
Explanation
The Joke
Lois Lane and Superman (Clark Kent) are discussing having children. Lois argues it is too risky because even if they successfully have a child, there is some probability it will be a super-child. Superman counters that society accepts them because their ethics align with its aspirations, but Lois raises the deeper concern: what about their children and their children's children? She points out that if they have a baby, they are creating a genetically superior species, and two such species cannot co-exist for long. Superman tries to argue against having children, but Lois turns it around: as the last Kryptonian, by choosing not to reproduce he is eliminating a superior species lineage. She concludes: "Either you certainly eliminate a superior species, or you possibly eliminate an inferior species, while giving rise to a lineage of heroes and champions." The final panel jumps to "30 years earlier" where a Kryptonian couple on Krypton decides to send their baby to Earth, noting that a few generations later there will be a whole colony of Kryptonians — implying the entire Superman origin story was a calculated breeding program.
The Humor
The comic takes the Superman mythos and applies ruthlessly logical ethical reasoning to the question of Superman having children. It is funny because Lois uses the same kind of cold utilitarian logic that a villain might use, but arrives at a conclusion that is hard to argue against. The twist ending reframes Superman's entire origin story: his parents did not send him to Earth out of desperation to save their child from a dying planet, but as a deliberate colonization strategy — send one baby, wait for interbreeding, and eventually you have a whole colony of Kryptonians on Earth. This retroactively makes Jor-El and Lara calculating eugenicists rather than desperate parents.
References
This comic references the DC Comics Superman mythology. Superman (Kal-El) was sent to Earth as a baby from the dying planet Krypton by his parents Jor-El and Lara. Clark Kent is his human identity, and Lois Lane is his longtime love interest. The concept of prima nocta (the right of a lord to sleep with brides) is referenced in the "All Hail Glornak" discussion of feudal customs.