As Americans we have a subconscious ability to place people into groups by the way someone looks, how they talk, their gender preferences, and what they believe. It is common because it is how we interact as a society. It is how we interact with each other, and we have it in our heads that we can determine who a person is in a matter of seconds. It is our way as human beings to justify the way we want to treat someone because it gets rid of the unknowns.
We don't like the unknown in society and our media. We need to know and get everything right away. Stereo Types is a way for us to quickly categorize people we may not understand and their actions so that we can justify the way society and us as people treat them. Women are to sensitive, is just one way of saying that "I don't want to watch what I say in front of them, or they are to hard to understand."
If we look beyond that we can see that everyone has attributes that are of all stereo types. That just because your a women doesn't mean your sensitive, and just because your a man doesn't mean that you cant share your feelings. Each person is different and has different attributes and tendencies and shouldn't be categorized.