Someone in my office says the character's gender was not defined; I thought Yoda was clearly male. Which one is it?
The Empire Strikes Back script treats Yoda as male:
LUKE: I'm not looking for a friend, I'm looking for a Jedi Master.
CREATURE: Oohhh. Jedi Master. Yoda. You seek Yoda.
LUKE: You know him?
CREATURE: Mmm. Take you to him, I will. (laughs) Yes, yes. But now, we must eat. Come. Good food. Come.
With that, the creature scurries out of the clearing, laughing merrily. Luke stares after him. All he sees is the faint light from the small power lamp moving through the fog. Luke makes his decision and starts after the creature.