Google Adwords is getting smarter as it is allowing you to now render ads as per gender and age profile. Earlier they had only location based targeting. This is a good feature as for example on Valentines day a flower seller can target the young crowd as compared to serving his ads more than age 40 age group.
Google is able to achieve the same as it is analysing each user search behaviour by virtue of your web surfing and storing the cookies on your computer.