Is tails a girl or boy

Tails is indeed a boy.


Courtesy of Wikipedia entry on Miles "Tails" Prower: http://en.wikipedia.org/wiki/Miles_%22Tails%22_Prower#Concept_and_creation


Yasushi Yamaguchi, originally the main artist and zone designer for Sega's Sonic Team, designed Tails for an internal competition for a sidekick to the speedy hedgehog. The character was meant to hold a "deep admiration for Sonic." His entry won, but Sonic Team decided to change his character's name from "Miles" to "Tails."
Yamaguchi ended up with a compromise. He sneaked the name "Miles" in as his legal name; "Tails" would be his nickname, ending up with the full name of Miles "Tails" Prower which is a pun of the phrase "miles per hour".
The character debuted as Sonic's tag-along partner in the franchise's second game, and has remained an important player since. However the character's uniqueness wasn't established until Sonic the Hedgehog 3 when players were given the power to control his flying