How is heteronormativity reinforced in current top-rated songs and TV shows?

I think that heteronormativity reinforced in current top-rated songs and TV shows by only showing the right way to life that Sociology think that we should live our lives because it is the Sociology's believes what be a norm. But what is a norm anyway? A norm is Social norms are the accepted behaviors within a society or group. This sociological and social psychological term has been defined as "the rules that a group uses for appropriate and inappropriate values, beliefs, attitudes and behaviors. These rules may be explicit or implicit. They have also been described as the "customary rules of behavior that coordinate our interactions with others." http://en.wikipedia.org/wiki/Norm_%28social%29.  In Songs, the same thing too.