Mr. Laser Beam wrote:
^ Actually the character in TOS was JoaQUIN, not JoaCHIM. And it seems clear that Joachim is too young to be the same person anyway.
In the novels, Joachim is Joaquin's son; when Joaquin is killed, Khan raises the boy as his own.
He is also to old to be born in the 20 year time period. So he had to be born on Earth and escape with his dad Joaquin aboard the Botany Bay.