It just had to happen.
Batman gained a female counterpart in 1956 in Batwoman, just in time to head off these freaky academics who were convinced Batman and Robin were P-Town buddies.
Readers had to wait five years for the next obvious addition to the Bat-Family.
In “Bat-Girl!” in “Batman” No. 139, cover date April 1961, written by Bill Finger and drawn by Sheldon Moldoff, the Bat-Family has been cornered by those dastardly fiends, the Cobra Gang.