what does lady macbeth acknowlege about gender sterectype-both for her and for him?

She says that Macbeth is "too full o' the milk of human kindness/To catch the nearest way."  He is too nice to simply murder Duncan in order to obtain the throne.  She has to ask to take away some of her feminine feelings in order to act "tough" so she can aid Macbeth in the plan to kill the king.