This struck me over the bank holidays, watching family reactions to my DD and DNephew, who are a similar age (3 and 2.5). For example:
DD runs about like a loon, jumping on and off the trampoline, doing roly-polys etc. Comments: 'Ooh she's so flexible! You should send her to gymnastics/ballet'
DN does the same: 'Ahh, boys are so physical aren't they? So rough and tumbe. He's a real boy!'
DD lets my niece dress her up in a fairy outfit: 'Ahh, little girls love dressing up don't they? Ahh, she's so pretty'
DN puts his big sister's pink shoes on: 'haha, poor thing having a big sister, he's just copying what she does'
DD has a bit of a strop: 'Ooh, she's a bit of a diva isn't she? What will she be like as a teenager? Haha'
DN has a bit of a strop: 'little boys are so agressive aren't they?'
In actual fact they are both just being toddlers, surely? I'm so sick of all the gender stereotyping I hear... boys love their mummies, girls love pink, boys are aggressive, girls love their daddies. They are all just kids with different personalities.