ARRRGGGHHHHH!!! MUST DEFEND SHEIK'S GENDER.

Sheik was originally male. Here is proof. 
[hider=Proof][http://imagizer.imageshack.us/v2/1024x768q90/843/tvhn.png][/hider]
Does that look girlish to you? Do you see those pecs and masculine thighs?

What better way to hide from Ganondorf than to become your opposite gender. He was looking for a Hylian girl not a Shiekah boy. Nintendo changed it when Sheik was added to Super Smash Bros. because they thought Zelda gender swapping would be a little to weird for the kids. They got away with more in the N64 era. I mean did you guys see Conker's Bad Fur Day? 

So Sheik was originally male, as such I see him as a male.