Anthony DeanToday's the birthday of Arthur Curry Jr., aka "Aquababy." (Also included: Andrina "Andy" Curry," a daughter recently introduced.)
(Art by Ivan Reis, Dario Brizuela, and Miguel Mendonça.)
Arthur Curry Jr. was killed by Black Manta a few years after the 1976 DC calendar was published. Though this apparently doesn't apply to some spin-off media.
Modern superhero comic writers don't seem to like writing babies/kids (seen as "useless" for the plots), to the point some will take any chance to kill them off or artificially age up the characters to teens (see: Jon Kent Superboy). Teens are seen as useful "mini-adults" (since they can date, hold jobs, be superheroes, etc.) and are more marketable to the target audience (superhero floppy comics haven't been kid-friendly in decades).
Aquababy in the Scooby-Doo story talks with the Hulk-like baby talk toddlers in Silver Age Superman stories used (see "Superbaby" stories).