Rule 63 [rool-siks-tee-three]
Rule 63 is a rule of the internet that reads as follows: "For any given male character, there is a female version of that character." This rule's exceptions are only in the instance that A: the male character is already so androgynous that a female version would be basically the same, or B: the female version hasn't been drawn yet.
EX. Rule 63 isn't just a rule of the internet. It is a constant in all matters of science fiction and fantasy dating back as long as their has been possible fiction. This definitely deserves some further examination with lines drawn to why our society is obsessed with gender identity. Expect a full article at another time, after some additional research.