But usually, you can guess. For example, you would know for sure that romantic films will NOT get the interest of men. And you would know as well that Sci-Fi is not really a girl thing.
But when I go to the cinema, I generally see women and men watching Sci-Fi or a bit of romance!Well well well. It's true, and thanks to the studios! Today, most films tends to have several genres! For example, in every action movie you will have a bit of romance. And that's because they want to have a wider audience.
52% of the bow-office in the UK, in 2009 was action, comedy and animation movies. This doesn't surprise me, as they are part of the widest target audience.
The BBFC have different ratings for films, according to their content in violence, sex or even the appearence of drugs or guns. This limits the target audience of films.