Recently Google offers the Demographic site Selection for its advertisers. Through the DSS (Demographic Site Selection), Adwords advertisers can now target  their audience for their ads by age, gender, income or other categories.
What’s Demographic Site Selection anyway? Google answers:

Demographic site selection is a way to find and run your ads on sites with the right audience for your AdWords campaigns.

A demographic group is an audience that shares a particular trait or characteristic. This trait might be age, gender, income, or some other factor. If your product appeals to young women, for instance, you might want to target sites popular with the female demographic, the 18-24 age demographic, or both. (LINK)

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