Ds is 3.5. We went to pils' house at weekend and when he got a bit overexcited and was shrieking they told him off for shrieking 'like a girl' and then later when he cried about something they again said something about crying 'like a girl' 
It really got to me actually. I don't see why the term girl should be used as an insult, I don't see why expressing emotion should be seen as a bad thing (although we are trying to curb the shrieking).
Pil are quite sexist generally- they have 3 ds and congratulated me on having 2 ds, seem to think that boys are 'better', v trad gender roles, disapprove of me working ft, etc etc.
I really want to say something to them but I'd sound like I wanker wouldn't I?