It is interesting to look at how young children perceive and apply gender.
This morning in the car:
Sarah: *holds up stuffed ram toy* This is lambie!
Me: Oh, but it's a RAM
Sarah: Yes, a lamb!
Me: No a ram, it's a boy with horns. It's a boy sheep. A lamb is a baby sheep which wouldn't have horns like that yet.
Sarah: I know it's a boy!
Sarah: I know if all my toys are boys or girls.
Me: Oh? What are the blocks?
Sarah: They are nothing.
Sarah: They don't have faces.