Sexism among the mini masses

I'm horrified to discover that my tot is a bit sexist and a little bit girly which I'm not so am having to adjust my way of thinking. She has definite ideas of what boys and girls should do. Here are a couple of examples:

• When asked who she plays with at nursery she gives me girl's names. If I ask about any of the boys, she looks at me with exasperation and declares that "They are boys, boys play with boys mummy". This even extends to friends we visit where she will only play with the girls. The only exception is when there are only boys and she will then want to join in but goes all girly if they want to do anything involving mud or monsters (except dinosaurs grrrrr)
  
• She refuses to wear or use anything blue and is determined to only wear or use pink, purple or red. Of late, she has conceded and will wear light blue so perhaps this example is a short lived.

To an extent, nurture is to blame as she has only girl cousins to play with. However, there have been boys in her circle of friends (until the age of 3 that is), and she sees plenty of examples on TV of boys playing with girls (Ben and Holly, Noddy and Tessy Bear, Tinkerbell and Terence, blah blah, yes we watch a lot of TV I'm not ashamed to admit it).
It's all bizarre, and in some cases leads to a mini case of Mean Girls since she isn't the only girl with these views and then they all act like teenagers (which just cracks me up, naughty mum).

On the bright side, we should encourage this as come her teenage years, we will be trying to keep her away from men as I'm not having some oink mess with my princess. Anyway, it's for their protection really as we know that the female of the species is deadlier than the male.