According to MRI+, only 26.1% of women ages 18-49 drink beer.
Here are three reasons why I, a woman of 22, do not choose beer above other beverages:
(1) Taste & Smell - I've never been able to finish a beer after first tasting it. (Granted, I was never really allowed to at the age I sampled them.) I do not find the smell appetizing, nor do I enjoy the flavor in combination with the carbonation.
(2) Alternatives - If I want a cold drink on a hot day, or alongside a slice of pizza, I'll go for a Coke on ice. If I'm celebrating with friends and wish to feel a "buzz," I'll enjoy a shot of tequila (or two, depending on the occasion) or a fruity mixed drink. Furthermore, why would I drink five beers to achieve the same intoxication with only a couple shots, or a really powerful mixed drink?
(3) Perception - I perceive beer to have masculine qualities. Though I don't consider myself to be overtly feminine (what with my taste in movies, rock music, clothing, etc.), I do not wish to associate myself with being "manly" on the occasions during which I drink alcoholic beverages.