Adwords advertisers will now be able to enjoy the fruits of demographic bidding at Google - a feature that lets advertisers target ads to users of a particular age group, gender or a combination of the two. Demographic bidding can be used with contextual or placement targeting and with both CPC and CPM bidding.

From Inside Adwords: Overall, demographic bidding gives you more control over the demographic groups who see your ads. You can also use demographic reports, available in the AdWords Report Center, to get insight into how your ads perform for specific demographics. These metrics can help you decide how to adjust your bid modifiers and restricts to reach the audiences that give you the most clicks and the best ROI.

It's important to note that demographic bidding is different that demographic site selection, which helps advertisers find and target entire websites (based on Comscore data) that have the audience that is trying to be reached. Conversely, demographic bidding lets advertisers modify bids or restrict the visibility of the ad based on the demographics of the users viewing that advertisement in the Google content network.